[Gary H]

Originally Posted by 77 TRASHCAN

Steve,
Jay sold that car, years ago. I have not heard about it since.....

Jay's old car is here in Jacksonville. He bought it from Jay without an engine and transmission. I built in him a KRE D port 455 for it and he drives it on the street. Still a beautiful car!

[Cliff R]

"Related, there is a bunch of work hiding under the hoods of these F.A.S.T. class race cars and far a far cry from using lightly modified factory intake manifolds.....

Jay DeLaigle's 1974 Trans Am.

His 1974 PONTIAC 455 "FAST Class" engine is a 501 CID Stroker !

HIS INTAKE- 1974 Pontiac EGR cast iron intake # 495106, Ported and flowed by Wilson Manifolds with support from Jon Kasse racing engines and SD performance."

There is a LOT of work hiding under the hood of FAST Class cars. I've been "involved" with them since the beginning and did the carb and distributor for Jay's FB. I've also done quite a few carburetors for others that race in the Pure Stock and FAST Classes. I wouldn't try to "downplay" the intake just because it's cut open, honed to the limits of the factory casting then welded back together. ALL the work still sits confined within the stock parameters. They are cut open simply to make access to many of the areas a LOT easier. If you think cutting open the intake is a little "intrusive" you should see what I do to the 897cfm Q-jets I build for them!.

It was a shame that Jay had to sell the car and get out of it. He did very well for the car chosen. It's a LOT easier to pick a combination where the car is lighter, and already uses factory cast iron "high performance" manifolds with a non-EGR intake.

Jay picked the 1974 FB non Super Duty set-up. The faster cars in that Classs for sure are going to be earlier cars like 68 FB's that are lighter, and have the RAII set-up. You are at least a second or two faster at the track before you put a dime into that adventure.....FWIW......

[Formulajones]

Originally Posted by Cliff R

He did very well for the car chosen. It's a LOT easier to pick a combination where the car is lighter, and already uses factory cast iron "high performance" manifolds with a non-EGR intake.

Jay picked the 1974 FB non Super Duty set-up. The faster cars in that Classs for sure are going to be earlier cars like 68 FB's that are lighter, and have the RAII set-up. You are at least a second or two faster at the track before you put a dime into that adventure.....FWIW......

Yes, that part of this type of racing is highly misunderstood, both in FAST and Pure Stock.

I've always found it impressive and been thankful that there are people that want to take on the challenge of trying to compete with a lesser package. They are at several disadvantages to start with but it adds diversity to the field which is nice to see. Otherwise we'd just see Hemis and L88 Vettes.

[Cliff R]

For those classes of racing it's simply about using the laws of physics to your advantage.

Start out with the lightest car with the biggest and most powerful engine in it.

Make sure that engine was a very good design for making big power like the Big Block Chevy, Hemi, Mopar 440's, Pontiac 400/455 HO/Super Duty, Buick 455 Stage 1, Ford 429, etc. That way before you start spending money you are a LOT closer to the "prize"........

[Cliff R]

Here is a "base" casting for a FAST Class Quadrajet. When finished with all three pieces they flow 897cfm and easily support 700hp. These are used almost exclusively for FAST Class racing where you must run a factory carb and modifications to it are allowed......

[NeighborsComplaint]

OP's:



ProComp:

[70GS455]

Originally Posted by Cliff R

Here is a "base" casting for a FAST Class Quadrajet. When finished with all three pieces they flow 897cfm and easily support 700hp. These are used almost exclusively for FAST Class racing where you must run a factory carb and modifications to it are allowed......

In addition to booster rings removed, it looks like the venturi has been removed from the primary bore. What details can you divulge to get it to flow so much?

Sent from my SM-G991U using Tapatalk

[scott70]

How street friendly is or isnt that carb Cliff?
I bought a 11/16" holley spacer that said it was for a quadrajet but the secondary openings were only 2" so I took a normal gasket and scribed on the spacer and ground them out to about 2.30" . I ground a little bit between the secondaries,,only about an 1" long and only about half the thickness of the spacer. We'll see if it does anything and I might even try a pass or 2 with no spacer at all.

[Cliff R]

Those carbs can be set up for the street and work fine. Problem is that when you loose the booster rings and put a small booster in the center of a large opening it's going to work more like a Holley or Edelbrock carb than a Q-jet or TQ. You will GAIN MPH and felt power when on the primary side only. Fuel mileage will fall off a bit, simply because you loose the sensitivy to the boosters and the fuel coming from them doesn't atomize/mix with the incoming air quite a well. To make up for the loss in "pull" from the main system and delay in getting on the main system you have to bring in a LOT more fuel from the idle system/transfer slots to compensate. Even with all that said these carbs are fantastic street and street/strip carbs IF you need that much carb on your engine and want to run a factory appearing Q-jet.

Most of the ones I've done for "Race" only run straight off the jets without a PV since you don't need a cruise curcuit to drive to and from the starting line and it takes some moving parts out of the equation. I'm working on the one in the pic at the moment, it's headed for a "455" Buick engine for FAST. I don't have my notes in front of me but it's over 600cid and will make over 700hp.

I've dyno, street and track tested the "897" cfm carbs and you woln't see any difference with them to past 600hp over a well set-up big casting with the rings in it. So I don't recommend the guy with the 1977 T/A with a 180hp 400 run out and hack the rings out of his Q-jet after reading this thread!..........Cliff

PS: Yes, that actually happened after someone read that chapter in my book. They had a 180hp 400 engine and removed the outer booster rings, took a "chainsaw" to the entire inside of the casting, then contacted me when it didn't work for chit.....DUH?

[trishieldchief]

What are the HP and TQ differences between stock and modified intake?

[Half-Inch Stud]

Originally Posted by trishieldchief

What are the HP and TQ differences between stock and modified intake?

Likened to keeping the Throttleplates at 3/4 open versus Wide Open, on a 455.

[Formulajones]

I think Dave had some of the before and after dyno results on his website.

I don't recall exactly but usually on a healthy 455 you might see 10-12hp and tq difference with the typical CNC job that Dave offers.

On smaller milder engines, not so much.

[Steve C.]

"I think Dave had some of the before and after dyno results on his website."

YES. See my post number 21 in this thread



.

[Half-Inch Stud]

Originally Posted by Half-Inch Stud

Likened to keeping the Throttleplates at 3/4 open versus Wide Open, on a 455.

Correction, if you agreed with Post #21, only CNC'd found 12 hp to be found. Hmmmm.

[400 Lemans]

Originally Posted by Half-Inch Stud

Correction, if you agreed with Post #21, only CNC'd found 12 hp to be found. Hmmmm.

And they found 14 hp more and 12 lb fthttp://www.sdperformance.com/newsStory.php?newsID=44 with a performer rpm.

[tc]

Cliff, didn't you go into some of the ports on the iron intake and change the shape of the arcs where the runners make their turn? Dave ( cnc ) does that too, right?

[Formulajones]

You can only get so far and do so much in the runners by hand or with a CNC. That's why the FAST guys are cutting those intakes apart, to port in areas that otherwise can't be reached, unless you want to spend the money for extrude honing, which the FAST guys also do.

[scott70]

10-12hp gain between a stock intake and a CNC ported one. It all adds up but that 10hp alone probably wont show up on your track #'s.

[Cliff R]

"Cliff, didn't you go into some of the ports on the iron intake and change the shape of the arcs where the runners make their turn? Dave ( cnc ) does that too, right?"

I've "worked" the iron intake that was the prototype for Dave's CNC program several times. Even so I made sure NOT to remove very much material from the runners. The goal was to make it as good as a "stock" intake could be without grinding it till it was paper thin in many areas.

Aside from opening up the plenum areas and giving it both bolt patterns like the RPM the actual work in the runners was more to smooth things out for optimum flow and stay close to the stock dimensions, plus I kept the port openings at the stock size.

Sadly I never spent the money to have an aluminum version made of it. The upfront costs to do it right with a USA based company just didn't look to me like I'd ever be able to sell enough of them to cover the costs and make a little money on the other end of that deal.

I actually still have the intake and will be offering it for sale here pretty soon as I'm cleaning up the shop and currently working on the parts room.......

[scott70]

Well I tried the 11/16" thick 4 hole spacer last night. Between the gaskets added up the 4 hole was only 1/8th inch thicker than the open divided 1/2" spacer. It was about the same performance. Mph and 60fts were the same. For the hell of it I took out the spacer completely and just used a stock 1/8th gasket for the last 2 passes. 60ft was immediately better by a tenth on both passes. Also coming up the return road and flooring it in 1st gear I could tell it had more pull from a low rpm.Mph was the same through out the night. Launching at a low rpm with my m21 and 3.31 gears it liked it...pulled through 1st gear gear quicker. It was weird though as I usually do a little standing burn out I had to push more on the throttle to get to 4000rpm while heating the bfg's. Did it both times.

With a auto trans and a little converter this all probably wouldn't mean anything. It would drive through this low end stuff quickly.