Anybody Actually Goin' Fast With a Holley 3 BBL?

[markjohnson]

As stated above, I was just wondering if anybody was having any luck with going fast with their Holley 3 BBL's? I know they were popular with Motion cars in particular and I've seen several cars restored with them, but I was wondering if anybody has tried to do anything serious with them lately besides just driving in and out of an enclosed trailer. I actually have two of them right now, a 950 and a 1050 both waiting for me to re-gain my patience again from working with them unsuccessfully in the early-Nineties. Now my father had one back in the Eighties that would just absolutely fly. No hesitation or anything, it would break the tires loose and accelerate 'til you saw God or the police seen you, whatever came first.

[69 Post Sedan]

Mark, I just noticed this thread. I would like to bring it up to the top. I am interested to hear what people say about these because I too would like to run one of these for the "Day 2 " look.

I have heard/read that they sucked and don't use it, along with it ran great on someone else's car. http://www.yenko.net/ubbthreads/images/graemlins/dunno.gif

Kurt http://www.yenko.net/ubbthreads/images/graemlins/beers.gif

[jtower1969]

I asked the same question to my Dad when I was doing my motor over..I was told a few ran good..most didn't. I went with a Baker Preped 950 HP Holley...Runs like a beast. http://www.yenko.net/ubbthreads/images/graemlins/3gears.gif

[markjohnson]

I had spent a lot of money on my 950 CFM unit, even adding a secondary metering plate to it, and was using it in conjunction with an old Edelbrock C427X dual plane intake on top of my L-88. I thought I actually had it dialed in and running good for a while there. Then one day I pulled it off for some reason I don't even remember and just threw on a box-stock 850 Holley DP and I gotta tell 'ya.....it felt like I had installed a Nitrous system because the car felt so much faster. Needless to say the 850 DP stayed on permanently and the 950 3BBL went into a box in the basement where it remains to this day.

[PxTx]

I think this is a pretty common experience with many people. Not described too scientifically so I'm gonna assume you don't have much data on the differences between the ways the carbs were set-up.

Motion commonly modified them with mechanical secondries, which then required the trick secondary squiter mod to help with the big secondary venturi opening.

Were both still vacuum secondaries? How about the accelerator pump configs like cam, squirter size etc?

The metering plate you referenced, did you mean a metering block, or did you install a modified/different metering plate?

I agree, they may be difficult to tune but there are better resources available these days. Joel made them run by puting them on a dyno and using an exhaust gas analyser to tune each circuit. Now you can use a wide band O2 and drive it on the road and log data.

I am confident that they can still be tuned to make respectable HP and decent drivability. Maybe not quite as good as a modern carb, but certainly within a few percentage points.


[ QUOTE ]
I had spent a lot of money on my 950 CFM unit, even adding a secondary metering plate to it, and was using it in conjunction with an old Edelbrock C427X dual plane intake on top of my L-88. I thought I actually had it dialed in and running good for a while there. Then one day I pulled it off for some reason I don't even remember and just threw on a box-stock 850 Holley DP and I gotta tell 'ya.....it felt like I had installed a Nitrous system because the car felt so much faster. Needless to say the 850 DP stayed on permanently and the 950 3BBL went into a box in the basement where it remains to this day.

[/ QUOTE ]

[Chevy454]

Some of the old guys over at Speedtalk said they were the stuff until the modern stuff came along...but you *really* had to know your way around a Holley, or it wouldn't work. I think Joe Sherman said his 3 barrel was 10-15hp up on his commparable 4-barrel at the time...?

[markjohnson]

Well Paul..........I'm sorry if it wasn't explained "scientifically" enough for you or that you didn't understand the Holley terminology. The 950 3BBL Vacuum Secondary was removed and the 850 DP (Double Pumper) was installed box-stock. This was done over the winter months while the drag strips were closed so I don't have any official drag strip numbers, but seat-of-the-pants revealed the 850 DP to be DRAMATICALLY faster. I had modified my 950 Holley 3 BBL (they didn't have jets in the rear, remember) with a kit that Holley offers that puts a Secondary Metering Plate (block, whatever) at the rear of the carb for easy jet changes, just like the front. As far as Joel Rosen is concerned, he obviously didn't think much of those Holley 3 BBL's in their out-of-the-box configuration and sold a kit to convert them to mechanical Secondaries. I believe it was called something like the "Motion Gear Drive Injector Kit". It included two meshing gears that fit onto the ends of the Primary and Secondary throttle shafts, thus allowing them to open at the same time and a very strange squirter on the Primary side that stretched across the top of the carb and discharged into the Secondary throttle bores. To many people and even Joel Rosen himself, this was the best way to get them to function decently. Now.....I may not have an EGT Monitor, but I've built and raced several 9-second street cars by the tried and true'd, old fashioned method of spark plug reading, so I really would like to think that I know a thing or two when it comes to dialing in a Holley, in particular to suit my purposes. I've gotten by quite well.

[396L35]

[ QUOTE ]

Well Paul..........I'm sorry if it wasn't explained "scientifically" enough for you or that you didn't understand the Holley terminology. The 950 3BBL Vacuum Secondary was removed and the 850 DP (Double Pumper) was installed box-stock. This was done over the winter months while the drag strips were closed so I don't have any official drag strip numbers, but seat-of-the-pants revealed the 850 DP to be DRAMATICALLY faster. I had modified my 950 Holley 3 BBL (they didn't have jets in the rear, remember) with a kit that Holley offers that puts a Secondary Metering Plate (block, whatever) at the rear of the carb for easy jet changes, just like the front. As far as Joel Rosen is concerned, he obviously didn't think much of those Holley 3 BBL's in their out-of-the-box configuration and sold a kit to convert them to mechanical Secondaries. I believe it was called something like the "Motion Gear Drive Injector Kit". It included two meshing gears that fit onto the ends of the Primary and Secondary throttle shafts, thus allowing them to open at the same time and a very strange squirter on the Primary side that stretched across the top of the carb and discharged into the Secondary throttle bores. To many people and even Joel Rosen himself, this was the best way to get them to function decently. Now.....I may not have an EGT Monitor, but I've built and raced several 9-second street cars by the tried and true'd, old fashioned method of spark plug reading, so I really would like to think that I know a thing or two when it comes to dialing in a Holley, in particular to suit my purposes. I've gotten by quite well.

[/ QUOTE ]
Settle down Mark, get off that computer and get that 62 running again.... http://www.yenko.net/ubbthreads/images/graemlins/beers.gif

[greg5436]

mark i had a 1050 and a 950 installed on my 69 l88 engine. i run the 950 all the time.1050 was hard to tune.but one day i installed a 850. it ran better and was more responsive. but the 950 looks correct on my car. greg

[PxTx]

Not trying to take a dig at you Mark about the lack of data on the carb swap. Sure, I can imagine swapping a newer carb and seeing gains right out of the box.

I figured it may have been an apples to oranges scenario, but I think we all were interested to hear some of the mods done to the 3 Barrel by you or others. I've done a similar metering plate to block update on my dual quad setup on my 65. Certainly helpful on tuning.

Yes some people find it easier to go faster with modern carbs, and it probably is. There is always an element of satisfaction when any of us can make this old technology run the number, don't you think?

I originally took your post as a request for a discussion on how to make the carb perform better. I'm not claiming to have all of the answers, but not posting specific the baseline configuration is a challenge. I realize it is not a thread requesting specific advise on how to tune your 3 barrel on your car either but I would love to continue the thread. At the very least I'll probably learn a few things specific to these carbs.

I'm also not trying to pick apart your statement, but fast and faster are both relative. I suspect the 3 barrel can be tuned for WOT drag passes just fine. The modern 850 you have will do this well too, plus have the benefit of improved drivability and throttle transitions.

How fast did your car go in the past? What ET do you expect it to make with an perfect carb config?

I've got a few of the mechanical secondary conversion kits, but I want to try my hand at tuning the 950 before I install one of those.

I agree plug readings can be a useful tuing tool, but if you've ever tuned a cab with adjustable air bleeds or emulsion tubes, there are circuits which contribute to acceleration which are hard to read by the plugs.

I'm not trying to talk down to you man, so if any of these statments makes you feel a little punchy I'm putting it out for the benefit of others reading the thread who may not have your experience. Are you and I okay?

[markjohnson]

We're fine. I'm feeling a little less "punchy" tonight. I like that word. Anyway, it's been many years since I messed with those 3BBL's. Just about 20 years ago, in fact, but a lot of it is still clear to me. I never had a chance to take that L-88 to the track while the 3 BBL was on it, but I did run it with the 850 and ran 11.70's with a 3.70 rear gear and I was actually pretty happy with it for the time. I have found another 3 BBL here in St. Louis that actually is already equipped with one the Motion Gear Drive Injector kits and it kinda peaked my interest in fooling around with one again. I'll add this too.......when I dis-assembled my 950 with that optional rear Secondary Metering Block, I noticed that the rear Secondary Boosters are a little closer together than they are in a standard 4 BBL and that the fuel passages in that metering block may not be lining up with the passages in the main carb body. Never noticed this when I first worked on it but I wish I would have. They say the Secondary Diaphrams are not manufactured anymore so treat any of them gently. Holley does make one that can be made to work (#135-6) but it requires some tricky surgery. As far as adjustable air bleeds, I have them on my 950 HP but have been advised by some people much smarter than me to leave them alone and I have heeded their advice. On an interesting note.......there used to be a Drag Radial class that required use of a single 4150 Holley (no Dominators) and we had talked of taking TWO used-up swap meet 3 BBL's and building a 'ringer' carb by using the large oval butterfly throttle plate on the Secondary AND Primary sides. That would have been interesting!

[Smokey]

What was or is the difference in your 850...and the newer versons of the 850HP? I'm blind on carb knowledge but let my dyno room friend help me with mine. I gained 29hp on my 396 with a new hp series over the stock 4346. But we are comparing apples to oranges again. And just think I used to use a 660 center squirter on it before I found the 4346.

[PxTx]

I beleive the centet squirters are specific for dual quad applications, so the idle circuit would not work well for 8 cylinders.

Interesting comment about the metering block on the 950. As for ajustable air bleeds, they are great for fine tuning, especially when A/F ratio is fat on lean in a particular area, but great otherwise. If you think of the fuel traveling up a soada straw and an air bleed as a crack in the side of the straw, fine tuning the fuel signal is a little easier to comprehend.

If goals for a 3 barrel are to be a low 11 second carb, I trust you can get it there. It would be nice to have some sort of baseline, but we can always start with the the mechanical kit and squirter mod and see where you are at.

Interestingly enough, Mark Hasset Jr brought a wide band 02 setup to tune the Phase III car with at this year's SCR. I really think it's a nice way to tune A/F whether we're talking EFI or carbs. Unfortunately, they broke a pushrod and did not get far on the tune.

Now I beleive Mark's Phase III L88 has run 11's, how deep into the 11's and with which carb I don't know. Maybe he'll see this and post.

[Salvatore]

In my days I was always told that a smaller carb that runs 85-90% efficient is better than a bigger carb that runs 60% efficient. I always had good luck with the 750 double pumper in the 70's on my LT-1 nova. That carb seemed to run better out of the box than the 780 I started with that had small modifications. I also was under the impression (from the guys who ran it) that the 3 barrel Holley was a bust. At least in the early days it was. Racers would put it on their LS 6 chevelles and slow it up in both et and mph. But like I said this was the 70's. http://www.yenko.net/ubbthreads/images/graemlins/dunno.gif

[Kim_Howie]

Talk about going to get toasted. I love my Carter carbs. They don't leak, there very responsive and idle better than any Holley I have owned. http://www.yenko.net/ubbthreads/images/graemlins/naughty.gif

[StealthBird]

The Motion gear drive kit was developed because back then, there was a definite attitude in enthusiast magazines that vacuum secondaries were for station wagons, not for performance. We know more nowadays of course. Vacuum secondary carbs produce just as much power as a mechanical secondary carb, they're just harder to dial in because they don't have a secondary metering block, just the plate. Drilling holes was time consuming, and swapping in a metering block was easy. Besides, you drill some holes in that vac secondary plate too large, you're sort of screwed. That's why most shops opted to replace the plate with a block, and then go to the gear drive. More of a shot off the line, in race trim, with slicks, but there's a lot to be said for vac secondaries on a street car. Once the butterflies are opened up, there should be no difference. The problem is tuning that secondary....

Just for the record, the larger Holley 3-barrel is a 1030 cfm unit, not a 1050. The only difference between the Holley 950 3-barrel (3916) and the 1030 cfm (4604) is that the 1030 uses dump tubes for the secondaries, no boosters, similar to the way the Q-jet works. The primary circuits are exactly the same as an 850.

I've been using a 1030 on the street for several years now, and have swapped back and forth with a 950HP. The 950HP is more responsive, understandable as it has smaller venturi. Wide open throttle, seat of the pants, can't tell a difference.

I know that's not scientific, just wanted to throw away a couple pennies today, so that was my .02 cents. http://www.yenko.net/ubbthreads/images/graemlins/smile.gif

[Plowman]

On the 1968 Dana of Brian H,has a Holley 3bbl,he is doing!

[PxTx]

I saw that, looked like they had the Eelco secondary squirter kit but with the vacuum secondaries left in place. Probably the best setup going!

[12secHonda]

[ QUOTE ]
Interestingly enough, Mark Hasset Jr brought a wide band 02 setup to tune the Phase III car with at this year's SCR. I really think it's a nice way to tune A/F whether we're talking EFI or carbs. Unfortunately, they broke a pushrod and did not get far on the tune.

Now I beleive Mark's Phase III L88 has run 11's, how deep into the 11's and with which carb I don't know. Maybe he'll see this and post.

[/ QUOTE ]

Yeah, I ripped the AEM wideband out of my Civic just before we headed to St. Louis this year. Was really looking forward to playing with jetting. But, the pushrod kinda ruined that plan lol. I'm no carb expert, so I wont attempt to go into discussing 3 barrel pro's and con's. But for what its worth - we did go 11.90's on one. That was with a 1.9 ish 60 foot and without really playing with the carb on a dyno or even using a wideband at the time...

[PxTx]

http://i61.photobucket.com/albums/h50/bkhpah/DSC_0010.jpg

Posted for a point of ref.

There are certainly tricks specific to make a 3 barrel run, and bolting on a newer- more tunable carb can be attractive. It's my intention to squease all I can out of the 3 going on Monica's L88.

Motion cars had a garantee of 11,50's right, so I suspect the ol' 3 had to deliver the goods.

[wheelhop]

Is there a Rosetta-Stone CD I can pick up to help me understand this carb lingo ????

[markjohnson]

I'll tell 'ya.......I agree that Vacuum Secondaries Carbs can be made to run hard, especially advantageous on a traction limited car. Up until a just a few years, Holley even had a 950 HP Model that was available with Vacuum Secondaries. We had one on a buddy's 454 Nova that ran 10.50-60's like clockwork on a 28-10.5 Mickey. It was a great carb and sometimes I wish I had socked that one away for a future application. Unfortunately, they were discontinued because everyone wanted the double pumper version.

[StealthBird]

My 3bbl still has the factory monster choke flap in place. the weird one with the two giant holes that, when the flap is closed, keep the boosters exposed. I went one step further and made a fast idle circuit with a solenoid. When you start the car up and pull the choke closed, it sets the fast idle to 1500 rpm. When you open the choke, the solenoid kicks off and the idle is back to normal. http://www.yenko.net/ubbthreads/images/graemlins/naughty.gif

[MultiMopars]

I agree, a vacuum secondary carb CAN run well performance wise and is far more street friendly than a 2x pumper.

[Plowman]

Bkhpah Dyno sheet on a 427 cu.in. the old 3 barrel on the 1968 Dana,peak at HP at 6400rpm was 642.1 at 4800rpm made 589 ft lbs of torque,THE OLD 3 BARREL!