Cliff's Quadrajet Parts and Rebuild Kits

Picked up a 17057216 at reasonable price and would like to use it on my 1977 GMC C15 with original stock 350 engine(no modifications) & auto trans.  Can you recommend a rebuild kit and offer any suggestions on what to look at and on getting dialed in?  Thanks.

I have a nice variety of jets and rods to work with now. Will block off the secondaries to assess primary jet performance. Once that’s good the rods will be dialed in.

So I said 6 but it could have been 7, it was regulated for Quadrajet use on the dyno and feeding the carb direct. This same thing happened with this carb on a different dyno a few years ago, but it ran so well in the car I just dismissed it as a fluke. In the car, this was running 12.4's-5's and never missing a beat and given the build and HP thats exactly what I was expecting, it was putting out the MPH that I would expect from the Holley pulls (435hp/516tq). It wasnt as lean at WOT as it is with this cam, but I never really bothered to spend a lot of time finding out either. The car has a AC pump and stock fuel lines.

Fast forward to this build, and the car is again on it's way to putting out the MPH I would expect from the new cam (441hp/544tq)  and while it's somewhat lean at WOT (13.5 if you trust a tailpipe bung), it runs great, idles clean and low, pulls good vacuum, great throttle response, clean fuel  delivery to 5700 etc..I just dont want to leave anything on the table.

I've got two other 540's, one built and testing, one ready to bubild. This car likes a lot of fuel and a lot of bypass with my current carb, but I may be covering for too much bypass with too much fuel because I just stairstepped my way into the current config till it ran right. I'd like to take a more scientific approach with the next two, and make sure I kick that Holley's ass. 

Lightning Boy, I'll throw some sheets up from the dyno sessions three years ago.while I dont have EGT's, there is more info there. I couldnt run the air flow meter cause we coulnt cobble it to the air cleaner base at the time and clear the dyno throttle linkage.

You do NOT need bars of any kind, most look like chit anyhow.

I won the Pontiac Nat's 5 times with two trips to the King of the Hill Race (last man standing) without any kind of traction bars.

First order of business is to weld the axle tubes to the carrier. 

Get some good tires.

Install sub-frame connectors and box/weld them in place instead of bolting them in.

Fabricate an adjustable pinion snubber to control the upward travel of the differential with good traction.  I simply modified mine by making a bracket and shims for it.

I would also recommend having a good driveshaft made with 1350 Brute Force U joints in it.  Billet yoke on the diff and slip joint for the drive shaft even better.

I like and use Chrysler SS leaf springs on my GM cars but you can get away with making clamps to stiffen up the front sections of stock springs if they are in good shape.  It's also a good idea to drill thru the stack of springs and replace the whimpy little bolts with 7/16 or even 1/2 grade 8 bolts that hold the stack of springs together.  Double check the welds on you leaf spring perches.  I've yanked them off the tubes a few times so just make it a habit of reinforcing those welds while I'm setting up the diff.

Replace the factory posi unit with a good clutch type. The Eaton unit is excellent.  The factory "S" and other type posi units are weak and spider gear breakage is going to happen, IF you are making any kind of power at all and find good traction.

Mosier axles are also a nice upgrade.  I prefer the bolt in variety vs the "C" clip versions.

I know all of this sounds like "over-kill", but at the end of the day you will be able to "hit" the suspension with full power, hook hard and lift the front of the vehicle without twisting the chit out of the chassis or breaking something.

WAY back in the late 1990's I starting taking steps to make my 73 Ventura faster at the track.  I broke EVERYTHING behind the engine a couple of times before doing what is described above. 

Once all that was up to par I went another 25 years and broke nothing, even hitting it with over 600ft lbs torque and running 1.5 60' times. 

The best part about all of it is that there are no visible traction devices.  Bars look like chit on those leaf spring cars and not nearly effective at controlling diff "wind-up" as simply stopping the upper travel of the diff at the source instead of trying to do it out on the axle tubes........hope this helps some......

What fuel pump are you using?  Fuel delivery system to the pump?

6psi is marginal fuel pressure for the .135" seat for you dyno runs.  If you saw power loss or falling off around 4900rpms you were sucking the bowl really low.

I going to a larger fuel inlet seat doesn't help then it's telling you either fuel pressure is too low and/or fuel delivery inadequate for the power level.

I've never once in all the years of doing this been outran anywhere by a Holley or any other type of carburetor on the dyno or at the track, provided we took steps to keep the Q-jet full on hard pulls or hard runs........