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Zman1969
05-14-2021, 01:48 PM
I have a over the counter LT1 short block that PO had put a unknown hydraulic cam and was wanting to see what would be a good cam that may make this live on 93 octane I have no issues going back flat tappet or even a street roller BUT have to fit under stock Vette covers no poly locks want this to look like a stock 302

mildly smoothed 186 heads
472 intake

Lynn
05-14-2021, 05:47 PM
Last time I checked the LT-1 cam was still available from Federal Mogul.

I run one in my 70 spec LT-1 dressed to look like a 302 and I really like it.

I get a little ping with 92 (no 93 available around here), so don't know what it would do on 93. I use 100LL from the local airport.

firstgenaddict
05-15-2021, 12:42 AM
Which heads?
And what are the flow numbers -
Personally my opinion is - if you are considering a roller... DO IT!
HOWEVER call crower and give them the specs on the heads - flow numbers from .100 -.700 valve lift in .100 increments - YOU WON'T BE SORRY!

LT1vette
05-15-2021, 01:08 AM
I would run the LT1 cammed engine, set up by a an excellent tuner against, that roller...ANYTIME.
The LT1 is one of the most "under rated" engines built. They had to have the original, camshaft and the ALL the distributor main shaft and accelerator cam to run as designed.
Find all the original parts, especially the camshaft and dist internals, the properly jetted Holley and you won't be looking at very many tail lights at the drags and you'll get decent mileage...

SuperNovaSS
05-15-2021, 02:50 AM
I would run the LT1 cammed engine, set up by a an excellent tuner against, that roller...ANYTIME.
The LT1 is one of the most "under rated" engines built. They had to have the original, camshaft and the ALL the distributor main shaft and accelerator cam to run as designed.
Find all the original parts, especially the camshaft and dist internals, the properly jetted Holley and you won't be looking at very many tail lights at the drags and you'll get decent mileage...


Um, I’d take that bet. The LT-1 cam is a great piece but a properly chosen roller would walk all over it.

Jason

LT1vette
05-15-2021, 01:53 PM
Um, I’d take that bet. The LT-1 cam is a great piece but a properly chosen roller would walk all over it.

Jason

Yes...I'd run ya. Now the parts have to be comparable (lift for lift), streetable and on pump gas.
It took me a long time to realize the potential of the LT1 cam, it was overshadowed by the big blocks in its day. But I never got beat by a big block car, I was beaten by a "fuelie" cam car a few times, but I realized he had more money in his motor than I had.
The important part was getting it properly tuned....
Thx for the offer!!!

napa68
05-15-2021, 06:34 PM
Here you go. I just bought one........

https://www.competitionproducts.com/Elgin-Mechanical-Flat-Tappet-Camshaft-Lifter-Set-Chevrolet-Small-Block-242_254-050-459_485-116-LS/productinfo/ELGE904PMDL/#.YKATsahKiUk

As some others here can attest to, I love this cam.

In fact, I recently put a similar cam (but not the same....tighter lobe centers) and will probably be changing that out for this one.

I just works. Makes power past 7000 (provided everything else in the package is up to the task) and has manners off idle.

Hope that helps!
Tim

frankk
05-15-2021, 10:19 PM
Napa what do you mean, it has manners off idle. I would like to find a cam that pulls like the LT1 or better and has a lumpy idle like the 572-720. I had a Sig Erson part # written down from years ago that I wanted to try, but of course now I can't find it.

Lynn
05-16-2021, 01:02 AM
That is Elgin's version of the LT-1 camshaft. Exact same duration at .050 lift. To me, you are going to be hard pressed to find a better camshaft with those pop up pistons and stock 186 heads. Even if your heads are port matched, if they aren't hogged out, this cam flat out works. Eric Jackson (vintage muscle car parts) advise me to use this cam back in 2012 on my LT-1 even though that meant he wasn't making a sale.

Looks like slightly more lift, but then manufacturers sometimes play with those numbers.

Chev. recommended .024 and .030 valve lash, and Elgin recommends .020 and ,025, which would effectively increase lift. I would bet it it the old Federal Mogul grind, which was identical to the 178 camshaft from Chevrolet. John Z told me that FM made the over the counter version for GM. I have it in my engine and it screams pretty good. Barely any perceptible lump at idle. I don't go past 6500 because I don't need to with a 4.10 screw, next gear has plenty of torque. Stock Z/28 manifold and DZ carb and it gets rubber in all four gears, even with Competition Engineering traction bars and 255 60 tires out back.
Great street manners. Plenty of vac for power brakes. Don't know how you can go wrong. I do not have EDM lifters in that engine. But, I have NEVER, since 2012, had to adjust the lifters. I have checked them three times. All three times they were still on the money. I add one half bottle of GM EOS with each oil change.

Have a Fed Mogul cam in the box that will be going in the 70 LT-1 Corvette with EDM lifters to make sure we don't wipe a lobe. Will still use th GM EOS, which I use in everything that has a flat tappet and goes high RPM.

frankk
05-16-2021, 04:21 AM
Thanks Lynn for the reply. I have only 2nd hand experience with LT1 power and that comes with watching LT1's at the drag strip. I want to find something that will wind up there and also have a very, very lumpy idle, crackely lumpy

John Brown
05-16-2021, 05:01 AM
Here is some good reading on camshaft choice for street driven small blocks.

a-tale-of-two-camshafts-st-louis-ncrs (https://pdf4pro.com/view/a-tale-of-two-camshafts-st-louis-ncrs-164675.html)

napa68
05-16-2021, 02:16 PM
Napa what do you mean, it has manners off idle. I would like to find a cam that pulls like the LT1 or better and has a lumpy idle like the 572-720. I had a Sig Erson part # written down from years ago that I wanted to try, but of course now I can't find it.

What I meant by that, is you don't need to slide the clutch at all on an LT-1 cam. No cam burble at 2000 rpm (hence no jerking in a stick car). I can give you the cam part number that is currently in my 327. While I am fine with rough idles, it's not a primary requirement for me.

Here is the 327 I just finished. 10.5:1, pocket ported 461's, Z28 springs. Idle @ 1100 rpm Nothing fancy. Good to 7000.

https://www.youtube.com/watch?v=O7sXG-S5TC8

With it's current cam (which I'll get you the PN) it carries about 400 lbs of torque from 3500 to 5500. It does require me to slide the clutch a bit more and have a bit more initial timing screwed in than I'd like. I am going to get my wide band sniffer on it this week and see if I can tune around it. Otherwise like I had mentioned, I am going back to the stock LT-1 cam. I've built this combination before in a fuel injected 327 and it just plain works!

napa68
05-16-2021, 02:21 PM
Here is some good reading on camshaft choice for street driven small blocks.

a-tale-of-two-camshafts-st-louis-ncrs (https://pdf4pro.com/view/a-tale-of-two-camshafts-st-louis-ncrs-164675.html)

This is a great article to take note from. One of the fellows who penned this article, I have come to know through the years. There is a good amount of common sense knowledge that avoids the typical magazine camshaft of the week BS.

It explains why these LT-1's just flat scream and have manners at the same time.

I'm sure there are others here that have different opinions (which is fine). This just happens to be mine from a good amount of past experience.

Tim

Lynn
05-16-2021, 04:56 PM
JMHO, but if you want a lumpy idle, you don't want an LT-1 camshaft. Just know this; without variable valve timing or computer controlled opening, there is no "best of both worlds" once you go to the lumpy idle. You may have issues with vac for power brakes. The engine is finnicky, and more difficult to tune. But, it that is what you have your heart set on, your car, your money.

Personally, I would go with a roller. Anything radical will require pretty stiff springs. With a flat tappet cam, you will need to break it in with just the outer springs, then pull the springs and install the inners as well. Not that big of a deal if you have an engine test run stand, but a PIA to do it with the engine in the car; especially if you are working on a freshly painted car. Pucker factor increases significantly. Even then, and even with EDM lifters, you STILL run a chance of wiping a cam lobe, especially if it sits for long periods of time.

frankk
05-16-2021, 08:48 PM
Lynn and Napa all really good points. I have a numbers vehicle that gets shielded use, by that I mean its always shielded from the weather and abusive type usage. However I am not afraid to use the 327 motors I have and the lumpy idle is a huge turnon for me. I know whatever I build there is still ricers and new muscle that will blow me away, but at the end of the day when I back the car into the driveway and listen to that idle it will all be worth it

LT1vette
05-17-2021, 12:58 AM
This is a great article to take note from. One of the fellows who penned this article, I have come to know through the years. There is a good amount of common sense knowledge that avoids the typical magazine camshaft of the week BS.

It explains why these LT-1's just flat scream and have manners at the same time.

I'm sure there are others here that have different opinions (which is fine). This just happens to be mine from a good amount of past experience.

Tim

JMHO, but if you want a lumpy idle, you don't want an LT-1 camshaft. Just know this; without variable valve timing or computer controlled opening, there is no "best of both worlds" once you go to the lumpy idle. You may have issues with vac for power brakes. The engine is finnicky, and more difficult to tune. But, it that is what you have your heart set on, your car, your money.

Personally, I would go with a roller. Anything radical will require pretty stiff springs. With a flat tappet cam, you will need to break it in with just the outer springs, then pull the springs and install the inners as well. Not that big of a deal if you have an engine test run stand, but a PIA to do it with the engine in the car; especially if you are working on a freshly painted car. Pucker factor increases significantly. Even then, and even with EDM lifters, you STILL run a chance of wiping a cam lobe, especially if it sits for long periods of time.

A little info on one of the authors, Duke Williams. I have met him and had numerous emails back and forth with him when I built my LT1.
He worked for Chevrolet and with Zora Duntov. He knows the "LT1 cam" like no one else. He has valve timing set up specs that changed the characteristics of this cam, he KNEW how to set it up to get it to work. A humble but extremely knowledgeable man.

As for the vacuum problem..... What problem?? There was not another model built that needed more vacuum than a Corvette. Power brakes, vacuum headlight doors, vacuum windshield door, distributor.... If you had a lack of vacuum it was because of leaks in those specific systems, not the camshaft....

NorCam
05-17-2021, 02:44 PM
I'm going to wade in here with a couple of cam suggestions for someone who wants a somewhat lumpy idle, but still wants to retain some good driving characteristics. The first is an updated solid camshaft which serves as a great replacement cam for any small block from the 302 right up to a fresh LT1. Sounds pretty stout at idle, but still retains decent street manners with enough vacuum to run power brakes. At .500' lift with 247/254 duration on a 112 LSA, it has a tight lash (.012) with modern ramps. Best suited to a 4-spd car with some gearing, it's designed to run from 2300 up 6900 rpm. I found it was better from about 2800 up with a wide ratio stick running 373's. I recently recommended this cam to another sYc member and his 302 dyno'd at 365hp with this cam profile. In a stock LT1 build, I would imagine that the same gain would be appreciated netting close to 400hp with the additional cubes.

Comp Cams Nostalgia Plus 12-673-4 Mechanical Cam (https://www.compcams.com/nostalgia-plus-247-254-solid-flat-cam-for-chevrolet-small-block.html)

Idling in my green Z/28 with freshly built DZ 302 (Fast Idle) (https://www.youtube.com/watch?v=7s5vLfhR684)

Now...if you're looking for a very driveable cam with excellent street manners, a lumpy idle, and something that will garner some attention from light to light, here's another cam that Dave @ Crower recommended to me a few years ago and I am so impressed with. I ran this Crower 00471 Hydraulic Roller in a mildly built 350 LT1 with pop-up pistons and freshened 462 heads that had a little bowl blending done. The result was a great lumpy idle and a cam that worked really really well between 2400-6500 rpm. Sounded nasty at idle, pulled real strong through all gears, and was very smooth with great torque through the entire rpm range. The bonus with this roller cam was less valve train maintenance and the $hit assed grin I always wore while driving this one. The cam was so good, I am considering building another 302 and might run this cam again. It doesn't run up into the 7K range, but more than makes up in the 3500 to 6500 range.

Crower 00471 Hydraulic Roller Camshaft (Perf Level 4) 2400 to 6500 rpm
(https://www.crower.com/camshafts/chevy-262-400-series-350-high-lift-hyd-roller-cam-20.html)
Idling away in a freshly built 350 LT1 (68 Camaro Build) (https://www.youtube.com/watch?v=fHuA-FHpyRM)

And here it is on a nice 3 gear pull while I was breaking in the new motor. (https://www.youtube.com/watch?v=derg3uMqZHE)

NorCam
05-17-2021, 02:53 PM
On that Hydraulic roller motor, I ran the cast iron 462 heads with Comp 1.50 roller rockers, the short version of Crower poly locks, and the heads were easily cut for the Crower valve springs. They do fit under the finned aluminum Edelbrock covers very nicely, and also fit under the GM finned Z/28 covers but I did run the double-thick cork gaskets to get the right clearance. (gaskets can be seen in the pics below)

Such a great combo, and one of the biggest Hyd Roller profiles you will find. I'm sure those last 2 videos are a true testament to how well-mannered that cam really was at low speed, and how well it pulls up top. Made great vacuum for the power brakes and vacuum-powered headlights too. Great Camshaft!

https://i.ibb.co/bKwrBNw/IMG-0110.jpg

https://i.ibb.co/kKJSB18/IMG-0111.jpg

Zman1969
05-17-2021, 03:45 PM
whoa! hold up on that car wash boys! I didn't ask for a lumpy idle.
I want a cam that will allow this to run and not detonate it self to death being a 10.5-11:1 engine
the heads I did some mild bowl blending on no hogging out, the machinist that did assembly asked who ported them because he liked what he saw, never had flow tested but these are just street heads

If roller will fit under the Z28 valve covers I'm all ears

napa68
05-17-2021, 04:53 PM
This thread did take a life of it's own, and I'm guilty of losing sight of the OP. Having said that, I believe the LT-1 cam will need a splash of race fuel above pump premium to live at 11:1 (assuming normal head gaskets, timing curve, and carb calibrations). At 10.5:1, you may just get by.

Sorry for adding to the confusion!
Tim

Lynn
05-17-2021, 06:39 PM
I will take some of the blame. Mistook this comment as coming from the OP. It did NOT.

"I want to find something that will wind up there and also have a very, very lumpy idle, crackely lumpy."

frankk
05-17-2021, 08:34 PM
I am mostly guilty of going sideways on this thread. I do appreciate all the comments.

Lynn
05-18-2021, 02:10 AM
Back to the OP. Cheapest way to go would be the Elgin cam. ELGE904PMDL

Virtually identical to the LT-1 camshaft.

You are going to be right on the edge of detonation.

If you are planning to disassemble the short block anyway, and you want to have a little hedge against detonation, you could have .010 cut off the tops of the pistons. Would actually help turbulence a bit. You would want to have the rotating assy balanced, but I do that on every engine build. Cheap insurance.

If you are wanting to go roller, call Chris Straub at Straub technologies. He is on the cutting edge of camshaft technology for old school SBC engines.

Zman1969
05-18-2021, 01:45 PM
Back to the OP. Cheapest way to go would be the Elgin cam. ELGE904PMDL

Virtually identical to the LT-1 camshaft.

You are going to be right on the edge of detonation.

If you are planning to disassemble the short block anyway, and you want to have a little hedge against detonation, you could have .010 cut off the tops of the pistons. Would actually help turbulence a bit. You would want to have the rotating assy balanced, but I do that on every engine build. Cheap insurance.

If you are wanting to go roller, call Chris Straub at Straub technologies. He is on the cutting edge of camshaft technology for old school SBC engines.

no harm guys were all motorheads! thanks Lynn I was thinking going back to stock solid lifter cam but another I would consider are the off road cams #140 and #754 ? or stay with LT1? I'm not milling pistons staying stock. again I want this drivable on what's available at the pump

NorCam
05-18-2021, 02:11 PM
whoa! hold up on that car wash boys! I didn't ask for a lumpy idle.


You have gotten some great suggestions on SBC cams...and reply with the above?

but another I would consider are the off road cams #140 and #754 ?

Then you reference two cams that are very lumpy and long on duration? :hmmm:

3927140 Mechanical - 257/269 - .493/.512 - 112 - Off Road
3965754 Mechanical - 262/273 - .488/.509 - 112 - 2nd Design

I'm thinking you should maybe touch base with Comp Cams tech support. They can help you select something that will work better for your needs.

L78_Nova
05-18-2021, 04:36 PM
The GM off road cams are nice if you have lots of rear gear.
They are lumpy old school, No bottom end torque, goodness

And VERY easy on valve springs !!

I run a 140 with 1.7 rockers in my 72 nova 350 flat tops zero decked with 4.33 rear and fast burn heads.
11.60's @ 113.
Definitely needs good fuel. I add a couple gallons of 100 LL to a tank of 91.
Gary

scuncio
05-18-2021, 05:29 PM
Graeme, I have a very similar hydraulic roller on the shelf that I pulled out of a 406 years ago to swap in a solid roller. I think it's way too big to work in a 302, but I'm curious what you think, as I was strongly contemplating it myself.

I'm going to wade in here with a couple of cam suggestions for someone who wants a somewhat lumpy idle, but still wants to retain some good driving characteristics. The first is an updated solid camshaft which serves as a great replacement cam for any small block from the 302 right up to a fresh LT1. Sounds pretty stout at idle, but still retains decent street manners with enough vacuum to run power brakes. At .500' lift with 247/254 duration on a 112 LSA, it has a tight lash (.012) with modern ramps. Best suited to a 4-spd car with some gearing, it's designed to run from 2300 up 6900 rpm. I found it was better from about 2800 up with a wide ratio stick running 373's. I recently recommended this cam to another sYc member and his 302 dyno'd at 365hp with this cam profile. In a stock LT1 build, I would imagine that the same gain would be appreciated netting close to 400hp with the additional cubes.

Comp Cams Nostalgia Plus 12-673-4 Mechanical Cam (https://www.compcams.com/nostalgia-plus-247-254-solid-flat-cam-for-chevrolet-small-block.html)

Idling in my green Z/28 with freshly built DZ 302 (Fast Idle) (https://www.youtube.com/watch?v=7s5vLfhR684)

Now...if you're looking for a very driveable cam with excellent street manners, a lumpy idle, and something that will garner some attention from light to light, here's another cam that Dave @ Crower recommended to me a few years ago and I am so impressed with. I ran this Crower 00471 Hydraulic Roller in a mildly built 350 LT1 with pop-up pistons and freshened 462 heads that had a little bowl blending done. The result was a great lumpy idle and a cam that worked really really well between 2400-6500 rpm. Sounded nasty at idle, pulled real strong through all gears, and was very smooth with great torque through the entire rpm range. The bonus with this roller cam was less valve train maintenance and the $hit assed grin I always wore while driving this one. The cam was so good, I am considering building another 302 and might run this cam again. It doesn't run up into the 7K range, but more than makes up in the 3500 to 6500 range.

Crower 00471 Hydraulic Roller Camshaft (Perf Level 4) 2400 to 6500 rpm
(https://www.crower.com/camshafts/chevy-262-400-series-350-high-lift-hyd-roller-cam-20.html)
Idling away in a freshly built 350 LT1 (68 Camaro Build) (https://www.youtube.com/watch?v=fHuA-FHpyRM)

And here it is on a nice 3 gear pull while I was breaking in the new motor. (https://www.youtube.com/watch?v=derg3uMqZHE)

Zman1969
05-18-2021, 06:36 PM
You have gotten some great suggestions on SBC cams...and reply with the above?



Then you reference two cams that are very lumpy and long on duration? :hmmm:

3927140 Mechanical - 257/269 - .493/.512 - 112 - Off Road
3965754 Mechanical - 262/273 - .488/.509 - 112 - 2nd Design

I'm thinking you should maybe touch base with Comp Cams tech support. They can help you select something that will work better for your needs.

Graeme I didn't ask for a lumpy idle, but you recommended several lumpy cams for that guy
I did ask about the off-road cams, not because they are lumpy. IIRC I started the thread with questions am I not allowed to ask others? with my LT1 I have a blank canvas and I ask because I am not a cam expert I don't want do this over because I grabbed what sounded cool so please give a guy with little experience a break would you?

NorCam
05-18-2021, 07:06 PM
Your posts are confusing?

You ask for advice on an LT-1 cam, then jump in saying hold up...nothing lumpy? Then you post again the next day asking about two camshafts known as the lumpiest of the DZ-302 profiles?

Read that whatever way you want...

NorCam
05-18-2021, 07:17 PM
One further note since you took that whole suggestion out of context? If you call the guys at Comp's tech line...ask them exactly what will work best in a street-driven LT1 on pump gas.

You might hear some very similar advice to what you have already gotten. Out!

firstgenaddict
05-18-2021, 09:41 PM
The crower solid roller we put in the black RS/Z was a 636 gross lift intake and exhaust 277 intake duration and 281 exhaust on a 112 lobe separation,
The heads were basically stock 186's with a little blend on the 3 angle valve job, and gasket matched I gave the flow numbers from .100 to .700 in .100 increments to Dave Crower and he asked if I wanted to pull a number on a dyno or what I was doing. 69 Z28 with 4.10 a 26.5" tall tire and /2.52 first -
I told him I was not going to second guess his recommendations and I could care less about much other than it was going into a 69 Z28 which has power brakes.

The car made 13" vacuum at 1000 RPM and pulled hard through 7000RPM, was really EASY to drive. Can someone embed the player I can't get it to work.
https://youtu.be/e4BZbpTA_wI (https://youtu.be/e4BZbpTA_wI)


https://youtu.be/e4BZbpTA_wI

NorCam
05-18-2021, 11:04 PM
Dave Crower is a smart man. He's the one who put me onto that 00471 grind after I told him that I was building a 69/Z.

e4BZbpTA_wI

firstgenaddict
05-18-2021, 11:18 PM
Dave Crower designs the cam ramps to slowly set the valves onto the seats - this way it doesn't hammer the seats into the heads. He told me that with the runner volume of the 186's you have to get the valve up quickly and hold it there as long as possible in order to get the air in and that the velocity and VE would remain high because of the small runner cross section.

LT1vette
05-19-2021, 01:54 AM
Hi... Opinions will come from all OVER!!!

Spend some time either, learning how to set up the LT1 cam or find an Old time racer to set the car up for you.
You are "beating a dead horse" on what you think is a good cam, what I think, what the next guy thinks...

My thought, after I did some of the second thinking on changing to something "BETTER",....
GM/CHEVY had wayyyyy more $$ than I did, why not try to perfect what they said worked??

If you are going racing, then this is not the website to look for an answer. If it's going to be your weekend driver, the bang for the $$ is there, IT'S IN THE TUNING!!

Been there, done that, VERY SORRY I DIDN'T LISTEN...

firstgenaddict
05-19-2021, 05:22 AM
I am sure that if circumstances(technology, costs, etc) had allowed Chevrolet to run roller cams in the engines of the 60's they would have - they sure ran them beginning in 1987 when they had the opportunity.

I doubt that Chevrolet / Pratt & Miller /K-tech were seeking opinions when they went to Crower Cams and specifically Dave Crower to design the cams for the C5R and C6R racing programs.

That being said... My opinion is that anyone building an engine call the professionals at CROWER CAMS or the cam manufacturer of your choosing and have them spec the cam for your application.

Zman1969
05-19-2021, 02:09 PM
The GM off road cams are nice if you have lots of rear gear.
They are lumpy old school, No bottom end torque, goodness

And VERY easy on valve springs !!

I run a 140 with 1.7 rockers in my 72 nova 350 flat tops zero decked with 4.33 rear and fast burn heads.
11.60's @ 113.
Definitely needs good fuel. I add a couple gallons of 100 LL to a tank of 91.
Gary

thanks L78 nova simple answer of being low on torque


Your posts are confusing?

You ask for advice on an LT-1 cam, then jump in saying hold up...nothing lumpy? Then you post again the next day asking about two camshafts known as the lumpiest of the DZ-302 profiles?

Read that whatever way you want...

Jump in? I didn't ask about Lumpy sounding cam for the LT1. You jumped in with if someone wants a lumpy cam... so your post wasn't related to my initial post was it?

I appreciate all the other suggestions here guys Lynn I'm leaning towards the LT1 cam but was initially concerned about LT1 detonation as the 302's kind of missed that with the stock cam, right now my 302 with 3.31s and stock exhaust manifolds is a bit of a pig to get moving

NorCam
05-19-2021, 03:26 PM
so your post wasn't related to my initial post was it?

Yes...it was actually. Many of the cams that you were provided including the so-called "several" I suggested were very suitable choices for an LT1 build. The roller cam I suggested with its 236/240 duration is an excellent hydraulic roller camshaft for an LT1 and makes enough vacuum to handle power brakes as well as support the RS headlamp operations. You did also say in your original post that you had no issues with a roller cam...did you not?

I have no issues going back flat tappet or even a street roller
Well? That was a really good street roller. If it's a little too lumpy for you, then understand that the entire line of hydraulic rollers is easily bumped down a step or two to what becomes a very mild-mannered street cam, and is totally forgiving on the valve train. Something the guys at Crower could have easily helped you out with. Seriously...they work with everyday people to help select camshafts all the time.

All snide aside...good luck with your engine build. :3gears:

Zman1969
05-19-2021, 05:00 PM
thanks for clearing that up but with roller will be able to keep the stock Z rocker covers?
I don't see anyway you can with the poly locks

NorCam
05-19-2021, 07:03 PM
I have successfully run Crower 86050S Short Poly Locks with 1.50 Roller Rockers under stock Z/28 covers on more than one occasion. For added clearance, I've also added thicker cork gaskets such as the ones from Summit, or have doubled up with a set of regular cork gaskets and glued them together. Lots of clearance then but you can often get away with just the short poly locks noted above.

If you end up picking a roller cam that doesn't need as much spring, you could likely run a set of stock long slot rockers and use the regular lock nuts. I simply use roller rockers and screw-in studs as a performance preference, as well as added insurance against pulling a stud and maybe dropping a valve. There are plenty of reasons to upgrade the stock valve train on 186 heads when one has the chance. Especially when buzzing these things up to and/or over 6500 rpm as they were intended.

This one has roller rockers and poly locks with stock valve covers. If you look to the right side, you can see the thicker gaskets under those covers. (most people would have no idea it's rollerized, but I know, and that's all that matters)

https://i.ibb.co/HgJ8NMb/IMG-2945.jpg