here's the set up. 85 TA, 383 Stroker, vortec heads, edelbrock 750 elec choke carb and intake. Mallory dizzy and msd wires, t-5 manual trans.

problem:

slight, one time hesitation under light to moderate power in each gear. It happens right after I shift and introduce a little throttle. no other problems through out the power band. it also happens if i'm at a set RPM and slowly introduce a little power. it hesitates very slightly and then operates normally. this only happens when the car has been running for a while but it is not choke related because the choke is fully open as it should be at this time. it almost seems that it does not happen when the choke IS on.

i just had the carb and timing tuned. 36 degrees centrifugal and about 45 with vacuum. No detonation problems running on 93 octane.

The guy that tuned it said that my autolite 26's might not be a cold enough plug and he said that my plug gap of about .042 might be too big. any truth to this??? he also said i may have a fouled plug but it runs smooth (on all 8) the rest of the time.

i'm thinking accelerator pump but my tuning guy said he adjusted the travel.

any help would be appreciated.

 

It's easy to move the accelerator pump travel, count the turns, and move it back if you have to.

Have you tried increasing the idle mix rate (I belive the 4150 has fuel/air rate screws, not mixture screws).

It seems by your description that you're a little lean on tip-in.

 

I believe it is lean at tip in as well. I'm going to try to back the idle mix srews off a bit. I have them about 1 1/2 turns out for the lean stop so it may be too lean. Thanks for the help. I 'll report back.

 

i adjusted the idle mix screws and the accelerator pump and no change. I was reading the edelbrock tuning stuff they sent me and I think that the step up springs may need to be changed. their discription of the symptoms seems very close to mine.

has anyone had experience with a problem like this before?