Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

7045214, w/ complete kit from Cliff installed, recipe #2, WOT problem.

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429bbf:
the napa part no. is m60036     he said its made by MPE 6.5-8 psi 30gph my cost 26.49 if you do a little searching i see carter has the same part no.m60036. hth

351wpower:
Just for the Halibut. Have you tried running it with a fuel pressure tester hooked up. When  the power goes away does it just fall flat or are there any symptoms like stumbling, backfiring, ............ Your sure the secondary's are opening and the rest of your linkage is operating correctly. (I know the E-brock performer intake is basically an aluminum version of a stock cast iron intake designed for 2v to 4v carb swaps) and is great for engines that did not come with or is very hard to find a factory 4v intake for. Having said that they are not always plug & play. Things like the throttle cable and bracket might bolt up but depending on the carb used may not function correctly. Especially if the car was equipped with a 2v carb from the factory ( I know you said you were using an E-brock AFB but that also might be different enough to cause a linkage issue with the Q-jet)

Engine off, air cleaner off. Have someone press the pedal down to the floor and look at the carb now remove the throttle cable and by hand open it up does the carb linkage keep moving if so then your throttle cable is not opening the carb fully.

I'm guessing at this point you have already tried pulling the fuel line off (both ends) and blowing it out. Also if there are rubber lines like from the sending unit/tank to the steel like that runs down the frame (factory type connections) see if they are cracked, brittle............... There is always the chance it could be sucking air. Or if your running a lot of rubber hose it could also be collapsing somewhere or crimped enough that the problem only shows up under load higher RPM's.

BBF after market intakes are square bore are you using the special gold colored adapter from E-brock with gasket top and bottom. The adapter they say to use when running a Q-jet on any of there non GM. dual plane intakes.

Just some food for thought (These are the phrases used when you over 40')         

351wpower:
I just thought of something else to try. Does it only do this under load or will it do it in park as well. if it does bypass the entire fuel delivery system by using a gas can (a marine gas tank works good) and a length of fuel line. Start it up and run it up over 4000 RPM What happens. Problem goes away focus on tank, lines.............. if problem is still there then your left with the carb.

As far as the Buick GS 455 they used a high capacity pump (long body) but for non GS 455's like a 455 in a 225 or wagon................  they used off the shell GM pumps. If you look at what came out of the factory back then early/mid 60's big blocks with 2x4's 3x2's cross rams...............they weren't running race pumps.   

spluhar:
Have not used fuel pressure gauge while driving.  After 2 or 3 seconds of wot, it starts stumbling. 

Secondarys are opening fine, I can feel them as there's a point where the end of the primaries where the secondary linkage needs a bit more foot to swing them open. Linkage is adjusted properly, am using the bracket off of the 2bbl 400 and a custom 2 hole 2 piece spacer to adapt the carb.  I didn't want an open spacer due to the weaker vacuum signal, and a 4 hole was too shallow, with not a smooth transition from spread to square.  I haven't blown down the fuel lines yet, but I just put in a new pick up and sending unit, a few months before I switched carbs.

I would not attempt to bring my engine up to 4000 rpm w/ no load.  Too many things can go wrong.  I've personally had engine component problems (when I was young and stupid) from revving engine w/ no load (possibly broken piston or ring, no compression and severe oil blow-by), and was close by my buddy when his fan blade broke off while revving engine in the driveway.

spluhar:
Update.  I hadn't run my car hard for a bit.  I've changed out the in-carb filter for the in-line filter that I had on previously.  I got on it the other day and it ran hard up to 5k w/ no hesitation. 

I had the opportunity to go on a longer trip last week.  67 mile round trip, 80 mph the whole way (3200 rpm), on 4 gallons of super.  16 mpg average w/ a big block, 4500lb brick, running pretty hard.

The article that convinced me to try the Quadrajet was in CarCraft 08/01.  I bought the carb in 07.  I bought the kit in 2010.  Now it's on and it works as planned!

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