some cam help????

[aaronkl84corvett]

after a bunch of bad luck trying modern cams with original equipment heads and exhaust, I swore i would never try an aftermarket cam in a restoration but here I am again - considering options.

basically, i'm building a 70 LT1 clone - with some hot rod stuff.

1) the engine will be a .030 over 350 with a good forged rotating assembly - I'll be using either KB or DSS racing flat top single relief pistons, a shim gasket, and the new trickflow dhc-175 heads that look like LT1 heads - (60ccs) compression should be right at 11:1 with a .040 quench - i might clean the block .005 but I don't want to remove the numbers on the original 350 block in the car.

stock LT1 intake, wide ratio muncie, and 3.70 gears.

I'm adding factory AC to the car, which shouoldn't be an issue - i've run the L72/LS6 cam in an AC equipped big block without issue so...

2) exhaust will be the 64-65 ramshorn manifolds that have the 2.5" outlet, and will be running a true 2.5 dual system through Gardner N11 offroad mufflers.

For me the obvious GM cam choices are the 30-30 or the original LT1 cam. I've run both, and know just how they perform, and should be just fine in this car.... but i hate to leave free power on the table if it will work with these heads and exhaust.

I've yet to have good luck with a modern cam and cast exhaust - but i know the FAST guys are going crazy fast with exhaust manifolds and roller cams.. so.

I don't want to loose the street friendly character of the GM SHP cams though... so I'm looking at one of the old school Ultradyne Cams - ideally, Harolds old 294s replacement - which is a single pattern 282 adv (at .020) 248 at .050, and .503 lift - but with the manifolds, I'd probably get it on a 112 or 114.

Does anyone thing i'll gain anything by doing this? or should i stick with the 30-30 or the LT1 cam?

[L78_Nova]

Call Chris Straub... lots of power on the table IMO.

[ban617]

Call Bullet that’s who bought Ultradyne I believe

[NorCam]

FWIW I bought a Crower 00471 Hydraulic Roller because I had heard nothing but great things about this one for 350 builds. Just this spring I got around to rebuilding my 11:1 LT-1 motor in my 68 and used the 00471 cam with Crowers Hippo lifters, a set of mildly worked over 462 cast iron heads and a factory Z/28 intake with 4053 carb.

What an "excellent" choice in cams let me tell you. Great street manners, a broad torque curve making great power across the entire RPM range, and a real healthy sound to it that has a lot of people thinking it's bigger that it really is. Specs on the cam are as follows and I don't think anyone can go wrong with this grind in a street car. Best of both worlds when it comes to performance.

Performance level 4 - High Lift - Street/strip applications, rough idle, 2500 stall required. INT/EXH - Dur @ .050” Lift: 236°/240° RR: 1.5/1.5 Gross Lift: .555”/.559” LSA: 110° RPM: 2400 to 6000 Redline: 6500



5500 shifts during break in period

[Lynn]

I have no experience with TF heads. I have a 69 L46 engine in my Z right now. Same crank rods and pistons and heads as s 70 LT-1. I went with a Z/28 manifold and carb and the LT-1 camshaft. I am very happy with it.

Federal Mogul still makes a good copy of the LT-1 cam, or at least they did in 2012.

[firstgenaddict]

AC isn't a problem with the stock 70 LT1 cam - same lift and duration was used for all LT1's EVEN the 72 LT1 AC VETTES.
They just used a BB tach with a 5600 redline VS the 6500 redline in the "normal" LT1's to keep from slinging the belts. ALSO the compressor pulley is MUCH larger.
All that being stated...
I cannot give more accolades to Dave Crower at Crower Cams and allowing him to spec cams based upon the car and engine along with gear ratios...
HOWEVER the most pertinent piece of information is the FLOW numbers on the heads in .100 increments up to .700. You can make great HP Torque and still have good vacuum with WAY MORE cam than you would believe.
Crower spec'd a solid roller with 630 gross lift with a 280 duration on the 302... made GOBS of torque by 3500.

[NorCam]

I've had the pleasure of dealing with Dave a couple of times. Great advice and a good education came from those talks. I've been a big fan of their products ever since. As a matter of fact, I chose their 294FDP grind for another motor completed a few weeks ago. It can be heard running in this 383 video that was just built for my 69 car. It'll be topped with a Crossram and is also running the cloned Trickflow -175 heads. They actually flow really well.



Can't go wrong with Crower!

[x33rs]

I like those factory cams mentioned but there is power to be found. I like to build PS engines and then skirt with the rules. Camshaft is one area I find power with even just a little bit of wiggle room. Since you're playing without rules I'd go roller for sure and enjoy all the benefits.

On my DZ I built the 302 per the PS rules, which state duration @.050 within 1% and lift at the valve within 2% of advertised. To take advantage of this with the solid cam I employed some knowledge of a good friend/engine builder that knew what would work well with stock unported heads.

Stock lift is advertised .485 but when you figure lash at .030 lift is only .455 so we changed the lobe profile to .495" lift with tight lash of .014" so lift at the valve falls in at .481", moved the duration a pinch and put the lobe sep where he felt would work best with the manifolds and exhaust system being used. A little trickery with the cam but within the rules. I kept compression at a true 11:1 (didn't use the 1.5 allowance) so the engine would be happy on pump gas. I'll assume that is also one of your requirements. Keeping iron heads and 11:1 requires attention paid to off seat timing and intake valve events.

The result was 402 hp on the dyno at 6700 and held pretty flat to 7200 on 91 octane.

Here's a quick idle clip. Makes 9 inches of vacuum up here at 5,000 ft. and more like 13 inches at sea level, very docile to drive, wife daily drives it, and it knocked down 17 mpg on the last highway trip we made, with an M-20 and 3.55's. It would run AC fine, if these cars had AC that is.

https://youtu.be/IZ0HlEY7b74

Here's a driving clip shifting at 7,000 at about 1:20 in. I like the cam, it works well with the 3.55's and the 4.88's. Nice smooth endless power band but if I were you and not worried about rules, I would have went a completely different direction.

https://youtu.be/5vX6hVQ_cKw

[firstgenaddict]

Originally Posted by NorCam

I've had the pleasure of dealing with Dave a couple of times. Great advice and a good education came from those talks. I've been a big fan of their products ever since. As a matter of fact, I chose their 294FDP grind for another motor completed a few weeks ago. It can be heard running in this 383 video that was just built for my 69 car. It'll be topped with a Crossram and is also running the cloned Trickflow -175 heads. They actually flow really well.



Can't go wrong with Crower!

X10... pure pleasure listening to him describe cam shafts... the man is an incredible genius... take advantage of his EXPERIENCE. If you understand the mechanics of a cam he is something else.

[x33rs]

If you can get him. I assume he's a busy guy, I've had trouble getting feedback from him in the past. Just had a set of his best solid rollers fail in an engine here within 3,000 miles with only moderate (the recommended) spring seat pressure of 240 lbs.

I prefer to deal with Paul and Jeff at Koerner Racing. They dealt with Harold Brookshire for decades and are very familiar with his lobes, especially the newest stuff he was working on before he passed, which I understand no one else has access to. Some of the best stuff I've seen to date.