This project started after I decided to ditch the Edlebrock 1407 that was on the car when I got it and go back to the stock QJet. Beyond the ancient design of the 1407, I was tired of fooling around with hack throttle brackets and downshift cables. It also had no choke and that made cold starting difficult.
I have a 77 Corvette w AT & A/C (but not the original engine - I believe it's an L65 from a 72 Camaro). The original exhaust and intake have been replaced with a Weiand 8004 and Flowtech 11106FLT headers. Other than that, I believe the engine is stock. Heads, cam, etc. are original.
Before switching carbs the car ran OK. It was dog slow (as you'd expect with 77 gearing and a TH350) and drank a TON of gas, but it didn't miss or chug.
I found a couple usable 17057204 cores and used your rebuild kits to make one good QJet. I used Lars papers and tutorials to go through all the usual trouble points - years and years of dirt and neglect, worn shafts, bent linkages and tangs, weird float heights, clogged tubes, etc. I did my best to return the QJet to its stock setup. It has the stock 77/52 primary jets/rods and the CH secondary rods installed.
The only non-stock mod I made was one I read in your book: drilling out the idle mix holes in the throttle plate to .090. I felt safe doing this because both you and Lars commented that it was common to run out of idle mix adjustment on these carbs.
I report sadly that it has never come close to even the lackluster performance of the Edelbrock. I've checked and rechecked the timing curve, checked valve lash and valve action (fearing a wiped cam lobe), replaced plugs, cap/rotor and wired - no joy. I went so far as to get a wideband AFR bung welded into the header so I could check AF ratios. At idle I'm sitting at about 14/15:1. It idles great. When I give it gas it will go lean, but not crazy lean: 15-16:1. But it most definitely runs like hot garbage.
What am I missing here? Any suggestions? At this point I'm either going to box this up and send it to Lars and beg his mercy, or I'm giving up and buying a Holley.
Steve