Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

Trouble Tuning Inexperienced

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huntincowboy:
Ok I've been playing with the apt. I've managed to  get what I think is close but it's still giving a pretty bad exhaust pop (one) when you punch it in neutral as it passes through 1200-1500 rpm going up.

I was running vacuum advance but I took it loose and set timing at 12*. The mechanical advance has me at about 30 total at somewhere between 2-3000 rpm (I'm by myself can't check both, do rpm just by ear). With vacuum hooked up it's at like 53* in the same area. I probably need to back that way down.

The apt rods are even and I'm still getting no stumble on the right (driver side) idle screw when I turn it all the way in. The left one will get to a point that it affects idle.

Would something be clogged in that circuit?

huntincowboy:
I did check the idle tubes with a piece of wire and they are clear btw.

I just did a short low gear pull (mechanical advance only) and it's still popping in about the same spot under load. (12-1500 rpm going up).

Cliff Ruggles:
53 degrees would be a lot of timing on a relatively large engine with a tiny cam in it.  What is the compression ratio of the big 460?.....

huntincowboy:
It's about 9.5:1. I found my backfire issue l, and it's my fault. I had 7 &8 backwards in the firing order. I missed it because the wires cross over each other and I was seeing it wrong. Backfires have all stopped now but the driver side idle adjustment still has no effect.

I removed the blades during cleaning and I'm wondering if maybe when I assembled them they were not reinstalled close enough to get the right signal on that side?

huntincowboy:
Something else that I thought of that's probably useful info is that in order to clear the distributor with my air cleaner I have to run two 1" spacers. The top one is an open center spacer and the bottom one is a qjet to square bore that tapers. I'm not sure how much that matters either, but I drove the truck about 30 miles today and it ran great.

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