Holley 750 Double pumper modified by PRC $$

[White90GT]

I'm testing the waters here. I'm hopefully about to pick up a 950 Holley from Davinci since I feel like my motor needs a little more air coming in to match the needs of my 408.

This is a Holley 750 double pumper modified by Steve Taylor at PRC Carbs in North houston. Currently setup with 81 jets on all 4 corners, has an 850 baseplate, 4 corner idle/air adjustment, Jet extensions in the rear, milled choke horn, extended breather tubes, reuseable gaskets, powder coated Silver and black with PRC plaques on the bowls. Very good looking and great running carburetor. Absolutely nothing wrong with it. It has about 100 passes on it and maybe 15-20 street miles. I've had it on the car since February and have the receipts from PRC for the work he did totalling $500.

I'm asking $500 for it, so basically you're paying for the work Steve put into it and getting the carb free LOL.

The car cranks up with two pumps of the throttle and idles steady at 900 rpms after just 5-10 seconds of holding it up on initial startup. At the track or after warmed up, you don't have to pump the throttle, she fires right up and straight to idle.

281-804-3168
Carl

$500 is firm at this point.

[Blue91]

LOL. Too funny, considering many here told you a 750 was going to be too small for you in the first place.

[nintylx]

Not to bust your bubble but asking $500 for a PRC carb is just a little bit ($200) High! Drop the Prc from the add and sell it for less than a new HP-750 and you may be able to move it. BTW new HP-750 go for $519.

[FE_rex]

You do know a 950 is a 750 body on an 850 baseplate. If the PRC carb is optimized it won't run any better that a 950. You need to step up to a dominator if it needs more air.

Instead of paying a premium on someones name, why don't you just get a Holley from summit and run it? Most of these carb gurus don't do anything but build a carb to Holley specs and take your money. Unless you are paying BIG$$ you aren't getting much more than a good rebuild kit and cleaning would give you.

[White90GT]

Guys I'm not positive that its too small, I'm going to find out when I put the 950 on. I'm getting a good deal on a Davinci 950 and am just trying to get out what I have into the 750. The price stands at $500 until I try out the new one and get a little time with it to see how its going to work.
According to Davinci's site, their carbs flow a true 950cfm. It has a 950 Pro Form center section like the HP.

[Timebomb]

Listen to what Ken is saying, we have all told you that a 750 is too small and you are in denial that it is....if your current current 750 is maxed you aren't going to see any gains going to a 950 because of the design of the carb. Carb flow numbers are just like flow numbers for heads, every carb builder is going to give you inflated numbers as to what their carb flows so that you will by the product. Be sure you are compairing the carb to another under the same conditions and flow bench or you aren't comparing shit. You can try it but I'll bet you don't gain anything from it. You really need to put a dominator on it and swap the cams if you want to really pick up and make the most of your combination.

[MUSTANG BILLY]

I agree also that a bigger cam is need...Solid....For that Big of C.I. motor..That size motor is very capable of low 6's 1/8 no squeeze!

That motor does need a bigger carb so it isn't sufficating...... :D

[FE_rex]

Carl,
What I am trying to get across is a 950 main body has the same venturi size as a 750 main body. Look in the holley spec sheet and you will see that. Your a 750 body and an 850 baseplate is a 950.

[White90GT]

I picked up the Davinci 950 today. I basically got it for what I'm asking for this carb. I intend to compare the two side by side and take the car to the track with both carbs and similar jetting. I got a pack of jets from the guy to use until I get it tuned right.

These changes I make aren't costing me much except for tuning time since I can sell off the old part to make back the money.

Again I intend to do a same day comparison between the two carbs and adjust jetting accordingly. If the 950 doesn't work for me, you'll see it up for sale.

I've been reading a few carb sites and some are saying that a 750 can be good to 650-700 horsepower (flywheel) and I'm currently only around 550 or so flywheel. I got the 950 because it was a good deal and I wanted to try the bigger carb. I understand you guys are saying the venturis are the same, I'll compare them and get back to you on that. They "looked" bigger when I picked up the carb, but I don't have them side by side to look at.

[Blue91]

You don't listen to anyone on this site that has experience with this stuff, so why bother?

You HOPE to get $500 for that carb to break even.

[White90GT]

You don't listen to anyone on this site that has experience with this stuff, so why bother?

You HOPE to get $500 for that carb to break even.


I don't want to put a dominator on the car at this time. There are a few reasons for this: Hood clearance being #1. I run my 2.5" stormin norman cowl and like it, right now with a 1" spacer under this carb I have about 3" of clearance to the hood with no breather. #2 $$$ it would take money to adapt my intake to a dominator flange (without a 2" spacer). The throttle cable I'm using is cheap and I hear the dominators require pretty strong springs, so I'd probably need a better cable setup, #3, there are plenty of guys going fast with 950 HP series carburetors.

Some are advising I purchase a new out of the box 950HP carb and set it up myself. A new 950HP cost more than I've spent on the used carb. This carb was run on a 12:1 408 running the same heads I'm running, a little bigger cam, same intake and at 3000 lbs. He's been 10.20s in good weather and 10.50s in the heat which is what I want to see. The guy is a straight up guy that built the tube chassis ranger that this motor was in. He also did the rollbar install on Andy's Ranger. Like I said, he's even giving me a box of jets to setup the carb for my car then return.

Why do you give me $hit Fred, as I recall I'm the one out there racing every month and am trying different things to get a little more out of my combo. When was the last time your car went down the track again??? :trout:

[TxBandit]

With only 3" of clearance above the carb it'll never run right. You could put 10 carbs on it at one time and it still won't breathe right. You need a minumum of 4". Not 4" sitting in the driveway, 4" at the big end of the track when you're going 120 MPH and there's some downforce on the hood.

Also, based on what I'm gathering from this thread, you started with a used 750, then spent $500 on it. As I recall, it was suggested that you sell the 750 and get a dominator a long time ago. You could have easily gotten $200 or so for the 750, then added the $500 that you wasted at PRC, then bought a nice used Dominator for $400ish. You would have had $300 left over to spend on getting your manifold modified (it wouldn't have cost $300). At the end of the day you could have kept your hood, had a better carb and been running 4 or 5 tenths faster with less money out of pocket. But it's clear that logic doesn't apply in this case.

Troy

[Blue91]

My car hasn't been down the track in months b/c I haven't WANTED to go to the track. I can run right next to, if not faster, than your car runs at the present time and I have a weak/almost dead #4 cylinder on my car, unported heads, AODE, DRs, full interior and stereo system, and it weighs 3650lb. I am tired of the car scene at the moment and as such, I let my car sit in the garage. I can drive it any time I wish but I prefer to ride the R6 these days. I need to rebuild my motor, but I choose not to shortcut it. I've decided to LISTEN TO THE ADVICE OF OTHERS who know more about the topic than I do... when I rebuild my motor, it will be with correct, proper parts so the car runs like it should with the parts it has on it. Until I choose to do it correctly (I could do it NOW if I wanted, but it's not a priority these days), it will wait.

If you knew what you were doing, you'd realize it's easy to get more clearance under than 2.5" hood of yours. Hell, I'm under a STOCK hood.

[REX331]

Guys I am not a carb expert, but I did stay at a holiday inn express lastnight :thumb: The 950 Davinci should be good for his combo if its tuned right. Dominators are not required to make big hp. My brothers 408 CI SBC made 789hp@7900rpms with a Super Victor and Davinci 1000. No offense, but dominators are just not necissary for every combo. I didnt go with Davinci just becuase thats the first thing that came out of his mouth that I needed. Everyone else from Patrick at Pro Systems to Jesse at BIGS (whos carbs I have ran since building my 331) recomended a HP series carb. Now with the hood clearance. I guess I am in trouble too. Guess its time to go with a Pro Stock Scoop :)

Rex

[nintylx]

FYI My old 383 made 576HP @ 6800 rpm with hood open. (this was baseline after car was sold and dynoed in Oklahoma) I had a 4" lift off hood on the car and a supervictor with a 1" wilson spacer Hp950 and just a little over 3 1/2" of hood clearance. With the hood shut car lost 70+ hp! go figure.

[Timebomb]

With all the hassle that I went through to get my combo in the car I ended up with about 3" from the front of the car to the hood and 5" from the back of the carb to the hood. It's not optimal but with a 2.5" hood it's the best I could do. I will prpbably play around some after the car is running with some kind of carb tray to pull cold air into the carb only from the cowl area.

Rex, remember that forward facing hood scoops are not permitted in COTT Cheap Street!

[nintylx]

Also it is not the amount of air that is lost with a close hood clearance it is the sharp angle of the air that does not hit the boosters as it should!!!!

[FE_rex]

Why did the guy sell the Davinci? and Carl, this question is not meant to bash you or anything like that. Whenever anyone is selling a go fast part that is the bestest etc - you ALWAYS need to find out why it is being sold. Cause maybe you need to get what the person is going to.

It's funny I've seen induction go full circle. When I started racing no one knew how to tune EEC and went to the gurus but messed with their own carb. Now people go to carb experts and mess with their own EEC.

[White90GT]

Why did the guy sell the Davinci? and Carl, this question is not meant to bash you or anything like that. Whenever anyone is selling a go fast part that is the bestest etc - you ALWAYS need to find out why it is being sold. Cause maybe you need to get what the person is going to.

It's funny I've seen induction go full circle. When I started racing no one knew how to tune EEC and went to the gurus but messed with their own carb. Now people go to carb experts and mess with their own EEC.


Ken,
He is getting out of racing for a while and has already sold his longblock. He is trying to sell his truck as a rolling chassis. Trust me, I wouldn't buy a used part from someone I didn't get the story from and didn't trust would make it right if there were problems with the part. This guy was straight up honest. He ran this carb on his 12:1 408, he tried a dominator at one point and lost .2 and 2-3 mph (yes that was after they tried tuning it).

[White90GT]

No time to mess with the carbs today though, yesterday my wife's impala decided to run out of coolant and overheat and catch fire. Two front spark plug wires must have gotten against the header and melted causing a small fire. Luckily the head gaskets seem OK, but due to a known problem with coolant leaking around the intake, I'm replacing the lower and upper intake gaskets.
Not fun on a front wheel drive car.

[Thoroughbred]

Guys I am not a carb expert, but I did stay at a holiday inn express lastnight :thumb:

Rex
funniest one liner ive read in awhile..... :rofl: :rofl: :hail: :hail: