Anybody Actually Goin' Fast With a Holley 3 BBL?

**markjohnson** · #1 10-22-2009, 10:53 PM

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** · #2 11-05-2009, 01:28 AM

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.

Kurt

jtower1969 · #3 11-05-2009, 04:55 AM

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.

**markjohnson** · #4 11-05-2009, 05:25 AM

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** · #5 11-05-2009, 06:56 AM

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 · #6 11-05-2009, 07:05 AM

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** · #7 11-05-2009, 08:36 AM

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 · #8 11-05-2009, 11:12 PM

[ 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 · #9 11-06-2009, 04:47 AM

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** · #10 11-06-2009, 05:45 AM

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?