Anybody Actually Goin' Fast With a Holley 3 BBL?

[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....

[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.