General Category > Quadrajet Carb Talk and Tips

factory appearing stock tire drag racing

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69 stingray:
hi, new here and i have some questions, i have a 1969 corvette coupe originally a 427ci 390hp L-36 automatic car non power brakes, and non air conditioning. i was wondering if a correct numbered qjet carb. can be modified to work on a 520ci engine to run low 10's high 9's? i will have to use the correct intake manifold and correct cast iron exhaust manifolds and cylinder heads as far as casting numbers go, and we have to run a full 2 1/2 exhaust and stock tires. no power adder, no traction devices, and gas only, i wanted to use the L-88 engine parts (intake,carb. and heads since they are designed for higher rpm hp) and my goal is to run low 10's high nines. is this even possible? for the F.A.S.T. rules you can visit the F.A.S.T. website... i have seen a 69 L-88 corvette go 10.30's @ 130 in the FAST drags. so far they have 2 guys in the high nines dave dudak hemi and lane carey 71 mustang. thanks for any help  :)

Cliff Ruggles:
Yes, we built the carburetors that power Rick Mahoney's 68 FB's in both FAST and Stock. 

The early Chevy carb will work fine, needs some help as they are the smaller CFM models.  For FAST there are no limitations as to what we can do with them, just has to be "politically" correct for the application.

I have a few Super Stock cars in the mid 9's with those carbs (legal), so they are capable of keeping up with great power......Cliff

69 stingray:
hi cliff thanks for the quick reply, i think it would be so cool to run in the low 10's high nines with a quadrajet carb. because alot of people just wouldn't believe it. i just bought this car and it needs alot of work and a chassis replacement which i'm in the process of changing, my donor car is a 73 corvette automatic small block car, no rust on the frame at all. the current engine in the 69 is a 76 454 with an E4M carb. the motor i'll build for FAST is a dart block 4.5 std. bore, 4in. stroke 4340 crank, comp. cams #288-CR-8 mech. roller .714 lift, 254/262 duration @ 0.050 good torque, rpm range is 3,200-6,200. i don't have this cam yet but just one i'm looking at, maybe someone has a better idea? i want to build this right the first time. thanks for any help.... cliff do you have any older carbs. that will be "politically" correct for my application?

Cliff Ruggles:
I may have one big block 69 carb left in the inventory, but pretty sure it's the 7029200 for the low perf big block with auto trans.  Not sure how specific they want it to be for FAST?  Any carb from 69-74 would work equally as well, as they are all the same basic castings.

The biggest obstacle to running really quick with a q-jet is not the carburetor, it's the fuel delivery system.  Having only one needle/seat assembly you simply have to take steps to keep the bowl full on hard runs.  Getting the carb to do it's deal is easy.

My 455 cid powered "daily driver" runs low 11's with ease, stock intake, q-jet, HEI, 10" converter and 3.42 gears.  Full quiet exhaust on DOT's, pump gas only.  Here's a clip of a run year in August.  Even at near 4000' DA I have to retard the timing to 26 degrees, add weight, and shift at 5000rpm's to stay roll bar legal:


http://www.youtube.com/watch?v=6zVdoLR-VzM&feature=plcp

....Cliff

69 stingray:
hi cliff, i think you can change from different year carbs. as long as the cfm's are the same, nice video too! how small of a float can you use to help keep more fuel in the bowl? and are all the bowls the same size? i really need to contact the board members for F.A.S.T. so i know exactly what i can run. thanks cliff for your time and help and i'll be getting back here often  :)

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