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383 crate engine- What size carb?

12K views 10 replies 7 participants last post by  John D 
#1 ·
have a new crate from Scoggin Dickey on the way- the HT 383 crate w/ the LT4 hot cam. the engine comes with vortec heads. What size carb should I run since its a street car mostly with around 400hp. 600 edelbrock, 750 edelbrock? or 670 Holley avenger? or 750 q-jet? Let me know your opinions on this- I want max power, but dont what to loose cruising manners on the highway. Need torque for driving on the street. thanks.
 
#3 ·
If you have considered a Demon carb, go to barrygrant.com and fill out the form and they will recommend the demon carb that is correct for your application. The carb they recommended for me bolted on and performed perfectly. They wet flow their carbs so a 750 cfm carb really flows alot more cfm than a Holley. I think most peoples problems with Demons that you read about is due to the fact that the carb they are trying to use is to big for their application. I speak from experience. Thought I knew more than they did.You might try going to Pace chevy's website and see if the Demon application chart is there. It is in their new catalog. Good Luck but only do it once with proper reserch
 
#4 ·
the intake is an aluminum dual plane edelbrock performer RPM air gap. I will try barrgrant.com, thanks.
 
#5 ·
according to barry grants charts his 650 cfm speed demon is what I want. Holley is recommended 670 avenger or 750 double pumper. Edelbrock recommends their 750 carb. WHO DO I TRUST? I realize that 600 cfm is too small for a stroker, but how much more cfm does it really need? I dont want to starve the engine, but dont want to loose that bottom end throttle response. Besides, I cant afford a 400 dollar BG carb. Any other clues? What do you guys run on your 383 sbc? errr... for the street.
 
#6 ·
Good to see you are doing reserch but the demon will work to where the others will take time to dial in. The 650 Speed Demon probably flows 750 Cfm but will have the crisp throttle responce for the low end. By the time you buy two carbs that 400.00 will seem cheap. The Holley 750DP will work good but will take some trial and error to get your low speed drivability dialed in. Good carb but low speed crispness won't be their. I switched to the BG carb from the 750 and it was night and day difference crisper low speed and a hugh improvement on the top end I can say if $$$ are a concern to get the edelbrock carb choke works good and it is easy to tune but figure in another 50.00 for the needle kit. The other drawback will be hood clearance. You can not use a drop base air cleaner with this carb.
 
#7 ·
I run a Holley 650 DP on the 383 in my daily driver. I tried the 750 DP from my other car and it did not ET or MPH any better. I think I'm on the upper limit of this carb, but still works great. 3425 lbs, 3.42 gears, 2800 stall, 12.13 @ 111.9, whatever hp that figures to, I don't know.
 
#8 ·
alright, its come down to two carbs. The edelbrock thunder AVS 650 carb or the Speed Demon carb. I think I might spend the additional money for the speed demon. Will I be able to bolt this thing on and go?
 
#9 ·
Don't think you can really bolt on any carb and go. you will need to fine tune the idle screws for your particular engine.

I have the speed demon 650 with automatic choke on my 383. I had TONS of troubles because my speed shop made all kinds of adjustments to it so it would be ready for drag racing. Thing wouldn't run on the street.

After a lot of frustrations, I think I have most of it worked out.

Oh, and I have a 3" air cleaner with a drop base. it fits just fine to give me just enough clearance with the Performer RPM manifold under my '69 hood.

Dave
 
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