kidatforty
02-23-2003, 09:07 AM
Some of you know that I rebuilt my 350 buick engine and I had a bit of tuning issues. I thought I would run down some specs. of what I have accomplished with good results...finally! It has: 9:1 compression, 8 1/2 lbs.fuel pressure,pulling 8" mercury manifold vacuum, TA 212 camshaft with 4 degrees overlap, HEI dizzy from a 75 le sabre, 3" exhaust two into one with flowmaster 50. The engine fired right up but had awful tip-in. The following are the mods and settings I ended up with: Idle restrictions .027" stock / mod to .036" . primary main jets stock # 68 = .069" / mod to .073" . secondary mains stock #89 = .105" / mod to .110" . power valve stock #65 / mod to #35 . accelerator discharge nozzle stock .028" / mod to .032" . secondary diapragm spring stock black ( stiff) / mod to silver ( weak ) . float setting stock / no mod. . accel. pump cam stock / no mod. (yet). idle mixture screws 1 1/2 turns. Throttle stop screw stock / no mod. . slight opening of secondary throttle stop to admit more air. another very important mod. is to remove and grind the choke step-up cam to allow the throttle to close completely when choke is open completely. This problem was noted in a 4x4 mag but no cure was shown in the article. The spark plugs were upgraded due to HEI . AC Delco R45TSX gapped to .060" . torque plugs to 22 ft./lbs. Ignition timing (for now) 15 deg btdc / 30 deg total with vac diaphragm disconnected. It took a lot of research and fiddling to get to these numbers and mods. It works great and now it's time to put it to the off-road test. Probably next week-end. As some of you know I installed a brake booster vac pump off a caddy. It works excellent. I really dislike the transition from neutral to drive(automatic) so I will be trying a throttle positioner. I'll keep you posted as to the results.