NEED HELP!!!

[sumps]

I am new to olds engines. I am a chevy guy but i got this 1981 trans Am last fall that had a 403 in it. The car needed some tinkering and the previous owner didn't have much time to fix it. but I got it running, it has a 403 with under 1k on the rebuild, pumched .30 over, high performance cam, , mild porting on the heads and intake, had new rods and lifter installed, and the usualy new stuff, and I also have headers on it. I am runnning 650 holly.


Now I know this engine should be making some power, but when I step on it, there isn't much there, its like its only running on 2 barrels on the carb, accelerates slow. Then the engine tops off at around 4K rpm, then is will start to sputter, won't rev past that.

Any ideas? I know this engine stock has some torque because I have had a stock 403 trans am a few years ago and it could burn the tires off all day long. the car also bet a push rod, put new one in and it worked the same way

 

[sumps]

im starting to think its off a tooth on its timing, is it a hard job to get at its timing chain?

 

[megaladon6]

have you tried tuning the carb/timing? have you checked the fuel pressure/volume? are you sure the valves are properly adjusted?

 

[sumps]

i have tryed a diff carb(smaller carb) on it today same thing, going to take a look at the valves next time im at the car ill keep u posted any help is greatly appreciated

 

[Phoenyx]

Fuel pump maybe?

 

[Randy_W]

Timing; initial lead, mechanical advance, weak spark etc... Chain off is possible but you'll usually get other symptoms, carb not opening, cam degreed wrong, poor fuel flow due to bad pump, clogged or pinched line, clogged filter, etc....

 

[dogsht]

Take it to a real mechanic who likes old school performance stuff. Somebody who doesn't flinch when you tell them it probably has timeing & or carberator / fuel delivery issues and has worked with advance curve kits & stuff before. Your not dealing with fixing a broken box stock car but hoping to get somewhat of a performance tune while your at it. FWIW When its running right you may still have some issues which leave a lot of the performance on the table so to speak.

Actual static compression may be very low. Find out cam specs, what pistons it has, how much if any and what block deck or head milling was done and what head gaskets ie how thick they are compressed. It may be over cammed for low low compression. This would make it very lazy down low among other things and may be compounded by tall gears and a heavy car.

Depending on what you find and budget/goals there can be several different things to fix it or help remedy it. Two things probably regardless unless they have already been addressed are a higher stall converter and lower rear end gears. Even with modest street driver goals assuming modest cam and somewhat low compression just a 2,200 stall and maybe 3.23 over a stock stall and tall 2 series gears might make you crap your pants in comparison to a before and after.