Dual quad sbc application

[nubber]

No induction system yet and found a great deal on these. Two quick fuel Q series 750's carbs and a pro dominator tunnel ram, all new in box. Haven't bought yet, looking for opinions. Do you think this stroker is thirsty enough for this setup? Drag race only.

385 ci sbc stroker
scat 4340 crank 3.75" stroke
scat I beam rods 6"
4.040" bore
SRP dome race pistons, 13-1 compression
comp cam 249-12-908-9 solid roller cam
lift: .630''/.630''
duration: 300/308
afr 220 59cc angle milled competition heads with crower ss shaft mount

2350 lb chassis car
Glide with brake and 5000 convertor
5.13 gear, 7500 rpm shift

Thanks for your opinion, much appreciated.

[PackardV8]

Surprised F-BIRD'88 hasn't already gotten here, as he is a firm believer that if it ain't supercharged, it really wants a 2x4 tunnel ram.

(Of course, I agree with him most times.)

[chevyfreak]

Surprised F-BIRD'88 hasn't already gotten here, as he is a firm believer that if it ain't supercharged, it really wants a 2x4 tunnel ram.

(Of course, I agree with him most times.)

I like his idea with the 2xqjets for his 6barrel setup. .
But he will add his advise on the subject.

Chevyfreak.

[Alaskaracer]

Has nothing to do with "being thirsty enough". That combo will work fine once it's properly tuned. You're gonna hear that old wives tale phrase: "that's way too much carb for that combo"....or some bs like that. If that's the case, then a 330" small block running dual 1250's is way out of reality...but they are out there....

Make sure the carbs are set up for a tunnel ram application. They not only need to be matched, but the calibration will be different from a single carb application. You'll have two carbs supplying fuel vs. one, so basically twice the capacity. Fuel demands on each carb to supply the engine are cut in half. I'd have to look, but you're also going to want to make sure they are a progressive linkage, not 1:1. You don't want them opening that much that quick, it will affect low speed drivability...

Fuel delivery ideally would be either one two port regulator per carb, or one four port, depending on what you use. I'm a firm believer in overkill on a fuel system, you can never have too much delivery capacity. Whatever you don't use you can send back to the tank. I've ran both a single four port regulator and dual two port regulators, and I prefer the two regulator setup, but that's just me. Fuel volume will be important because you're feeding two carbs, not one, even though each doesn't need to deliver as much fuel as it would in a single application. A holley blue pump won't be enough, even though everybody will tell you it's more than enough...go big on the fuel pump, you won't be disappointed...Just because a car may only use X amount of fuel, doesn't mean a fuel pump that delivers "X+1 gallon" is enough. Lots of other factors to consider. For yours, I wouldn't have anything smaller than a 300 gph pump. But again, that's just me.

Sounds like a good fun combo though, should run well. I say go for it, you'll be happy you did once it's tuned...

[nubber]

Thanks for your detailed reply Mark. It appears those dual 750's can be tuned for the small block then, right on!
I was wondering about linkage styles.. progressive for idling around the pits driveability like you mention then it'll be to the floor for wot on the two step. Sound right? Thanks for the pump and regulator tips too.

[F-BIRD'88]

Yes the motor is thirsty enough.
You are at the bottom range on camshaft for this
but fine .. It may want more and more rpm (gears,, converter) to max it out and go absulute fastest.
These competition race T rams like to rev up...
Plan on dyno tuning it and then track fine tuning it to dial in the carbs.

It will run well reguardless.. Yes use progressive linkage on the carbs Try it both ways (drag racing)
Plan on launching at a higher rpm if 2 step....

Once its all dialed in i bet you find it more consistant overall than a single carb setup..

[F-BIRD'88]

Surprised F-BIRD'88 hasn't already gotten here, as he is a firm believer that if it ain't supercharged, it really wants a 2x4 tunnel ram.

(Of course, I agree with him most times.)

I like his idea with the 2xqjets for his 6barrel setup. .
But he will add his advise on the subject.

Chevyfreak.

I still am going to try this on both a single 4 bbl intake and on a blower motor .. (street stuff).

If I can come up with a sbc TRam with a removable plenum top or can build a custom plenum top I'll try it on a Sbc T Ram.
The gears turn slow here... $$$$

[F-BIRD'88]

Too bad Joe Sherman is no longer with us.
BigJoe1 He would advise you well.

He had a wealth of knowledge and experience on all things
Tunnel Ram And Going Faster than the average bear.

[F-BIRD'88]

The tunnel rams basic advantage over a big single race carb intake set up is it breathes deeper at the upper rpm range at near and after peak hp rpm.
Thus to use that advantage to go quicker and faster
down the track you want to gear it up to buzz higher thru the traps... Is this 1/4 mi or 1/8 Th mile racing?
V
Gearing is CRITICAL on sbc with glide car.

If you make your car a bit quicker and faster mph is that going to win you more money?
Do you run a Quick 8 quick 16 like program where you have to qualify low ET?

This is the SBC raceTunnel Ram I wanted my bud to use on his Nitrous ....18 deg head 406 SBC. Would have been less custom work and gone a bit faster .. But no dice.

[nubber]

Thanks bird!
That's great stuff, lots to digest. Im confident going ahead with this now.
As far as what class it will run its a real grab bag. 1/8th mile small tire friday nights and brackets sat-sun at elevation. If work allows maybe some sea level 1/4 mile road trips.
I'll post up some dyno numbers and pics soon.
Thanks

[Little Mouse]

Now you know world coming to an end F-bird did not say needs edelbrock carbs. Guess he is ok with it because you said the price was good.

[Alaskaracer]

With the progressive linkage, the primaries will open to about halfway first before the secondaries move. Then the secondaries will open quickly but proportionately to the primaries to WOT. They help prevent the sudden loss of vacuum below the carbs when they open, so it gives better part throttle drivability....

Even the twin 1295's on my junk were progressive...I haven't really seen an application where a 1:1 linkage was any better....