Engine Troubles, Please Help!

[85s10racer]

I have a 1976 Chevy police 350 short block with 1967 327 heads that are supposed to have big valves and The engine has a mild cam in it. Im running a Torker II intake with a Holley 650 double pumper. When in park, If I punch the throttle, the engine wall lag very bad, and when in gear the engine will hesitate and stumble when hitting the gas more than halfway. I have tried different amounts of timing, from 36 down to 12 degrees and it doesnt seem to help, I have also tried 4 different carbs and they all do the same thing. I have tried a Carter AFB, a Holley 600 cfm vac secondary, a Edelbrock, all with the same result. Please help! http://www.s10v8.com/images/smilies/icon_confused.gif

[355V8S10Tahoe]

I would suggest getting rid of the Torquer II manifold and put on a duel plane like an Edelbrock performer or performer RPM, it will respond much better...

[Ryoung68]

What is your fuel pressure set at? More Cam specs, where is the power band at? Is this engine for street, race or combination?

[Melonhead]

I agree with the manifold adding to the problem, but not the major part. The distributor you have, is it a stock off the shelf unit? Are you using vacuum advance? The one thing you didn't mention was fuel pressure. Are you using a mechanical or electric pump? Are you using a regulator. Most times a bog is due to too little fuel delivered for the air portion. The other is un-controled timing. Most of us use only mechanical advance, but limited for stock. This allows for more initail timing and stay within 36 degrees total. A stock distributor will give 30-32 degrees with mechanical and vacuum timing. A recurve kit can be used to limit the mechanical timing and changing the springs to suit the engine needs. Lighter springs will allow the timing to ramp quickly and heavier springs will slow it down. Point blank, a bad distributor and carb set-up will act like a lazy dog, can't get out of it's own way. Hope this helps.

[adh383]

first I would do a complete check for any vacuum leaks-- vac hoses-- intake gasket check-

[85s10racer]

I have tried running it with the vacuum advance disconnected and connected. Im not sure of what Cam is in the engine, but it is Mild. I am getting a Vacuum reading of 15-16 in neutral at 1000-1200 rpm idling. The distributor is a stock HEI unit, with new Accel Super Stock 8mm plug wires and new Autolite spark plugs. Today I took out the #28 squirters and put in #25, I took out the brown cams and put a white in the front and a blue in the rear, That helped a little, so I took the #72 jets out of the rear and put in 67 jets so it is the same as the front. It still runs has dead thump when I punch the throttle. This is all in Neutral too, it is worse when you put in gear. BTW, Im running a mechanical fuel pump with good pressure.

[oncearacer52]

Thats plenty of vacuum at idle. Just for the heck of it try a pink cam in the primaries.

[85s10racer]

OK, so it wasnt a brown cam, it WAS pink that i had in there before, it was just aged.

[85s10racer]

Also, forgot to mention, the heads are supposed to have like a 1.72 intake valve, but the guy I got it from says it has big valves put in the heads.

[gs97chevys10]

get rid of the leaded gas heads thats my thought

[Scotty_S-15]

On 2008-01-23 18:02, 85s10racer wrote:............................. I am getting a Vacuum reading of 15-16 in neutral at 1000-1200 rpm idling. .........................



Do you always have it idling that high? If so, why? I know you mentioned having a "mild" cam... http://www.s10v8.com/images/smilies/icon_confused.gif

.......... I know that a higher idle can sometimes help the "blahhhs" when you punch it.

[85s10racer]

OK, so today I pulled the heads and found...........The heads are 1.7 inch intake valves http://www.s10v8.com/images/smilies/icon_frown.gif BUT!!!!! The pistons are flat tops, and are marked J2165 .030 YEAH!!! Its a fresh 355, the cylinder walls are very clean and have good cross hatch and no lip at the top of the cylinder. I have a set of 1978 Corvette 882 heads that I pulled off a fresh rebuilt vette that threw a rod after it was freshened up. The piston did make contact with the head but there appears to be no damage to them or the valves. Should I look for something better or just use them? BTW, I think they have been machined