Hi V8Buick, My car will vapor lock after running for awhile. I notice that when I exit the highway it happens or after a little in town driving. I put in neutral after lights then goose the throttle to keep it running. This was not a happening before headers. The fuels had worn thin and leaked so I replaced them. I'm planning to installed an inline electric fuel pump in hopes of curing this ailment. However, I'm posting for tips and suggestions to my Regal going. Thanks in advance.
Did you adjust or rejet carb? Headers leans out the mixture. And double check for vacuum leaks as you may have knocked a line off also. Put a vacuum gauge on it and see where that’s at , a stock cam should pull 20 inches of vacuum.
There is no answer for that question. It will depend on what Q-jet is on the car now, and what the jetting and calibrations are (air bleed and such). In general, if you add headers, you'll need to jet up 2 sizes or more. You may also need to go up in primary rod size. There are 2 guys here on the board that specialize in calibrating Q-jets to your combination. Ken (techg8), and Mark (carmantx). PM them with your combination and Q-jet part number.
Send off th carb to be re calibrated... and build a plywood 1/2” carb spacer to reduce the heat to the carb... also use heat wrap on your fuel lines where they are close to the headers.
I bought a phenolic/wood 1/2 spacer from summit. It worked, but I had to hog out the throttle bore holes a little so the blades wouldn't stick open. Either no throttle or all the throttle, bad for any car.
Two vacuum hoses leading to air cleaner were not seated properly. After pushing them further inside the K&N filter, the issue subsided a bit. I have a 1" spacer from Summit that I have not installed yet because I'm considering swapping the '76 350 for a '71 350. In stock form the '71 produced more HP with higher compression.
Don’t count the 71 as having that much more power and compression. The 76 has about 7.7 compression, the 71 has about 8.2 compression. So it’s not really making much more. But since you do have it you can get it on a stand, do some work on it. The 76 has a bigger oil pickup tube and passage, so I would get a new 76 pickup tube, and drill out passage. Replace front cam bearing, preferably with a TA backgrooved one. Get a crower level 3 cam,advanced 4 degrees when degreed. A 2500 convertor, and some bowl porting/or big valves, competition valve job with the heads shaved some to bump the compression up. Get a distributer recurve kit, bring in the timing faster. And a Quadrajet Power built Quadrajet, or Everyday Performance built Quadrajet. You will see the potential then.
Steve is the man on that. Running higher compression, stock intake, exhaust manifolds. Runs 13.5 , his tune is really good. He says the later cam timing gives alittle more rpm on top end. Obviously it’s working for him.
Sean, I plugged the hoses going to air cleaner with bolts and I wrapped the fuel lines. The car is running 10x better. Having a blast driving it... Thanks for the wrap tip.
