late 70's 350 runs and idles like dirt!

My sbc 350 will stumble under acceleration and idle rough..
No matter what carb I put on her she runs like garbage!
I installed a new cap and rotor, new hei coil, new plugs (ac) and new wires!
It idles high in park but stalls in any gear.
Poor acceleration.
Plugs are burning chocolate brown.
no exhaust restriction.
There are no timing marks on dampener but there is a timing tab.
Any ideas?

Given the age and symptoms, perhaps your timing chain is really worn and the camshaft has skipped a tooth, resulting in retarded valve timing.

Beat me to it. Agreed.

Given the age and symptoms, perhaps your timing chain is really worn and the camshaft has skipped a tooth, resulting in retarded valve timing.

I did not pull the timing cover, is there any way I can tell if I have late valve timing without pulling the whole front of the engine apart?. I am running 15 Hg's of vac with a stock cam... thats not right!

I did change to another holley and seems to run a little better. I have better throttle responce and once warm it idles pretty smooth in drive but in order to have it idle in gear it must idle high in park. I put on an old quadrajet and seem to run awesome and didn't have the high idle problem but this carb stumbles a little and starts hard, worried I may blow my starter. I But my holley back on and ran ok except the high idle problem. I have 15 Hg's of vac and it flutters between 15-16 Hg's. Someone told me if I have a manual choke I need some type of special gasket... Can somebody enlighten me on this?

And if I sit at a stop sign too long the idle start getting loapy until i clear the cylinders.

As I was reading your update, I got thinking about perhaps needing a carb spacer, and/or a vacuum leak between the intake and carb.

As I was reading your update, I got thinking about perhaps needing a carb spacer, and/or a vacuum leak between the intake and carb.

Thanx.. I found a stripped bolt on the eddy intake for the holley setup. I ended up using a holley-quadrajet manifold adapter spacer. Used the threads for quadrajet to hold plate down then bolted the holley on top! Runs lots better.

Vac is running 18-19 Hg's now. I unhooked all vac lines and plugged vac ports and still have this low vac bs. Im sure better carb tuning will bring up the vac and so will timing. And again I may have vac leak behind manual choke bracket. And what is the proper way to set my accelerater pump?

My idle is alot smoother now and rpm don't have to be as high anymore in park to go in gear without stalling. Has to idle @1000r's in park to idle @600 smoothly in drive. And my distributor is fully advancing the second its plugged into a vac port... this does not seem right.

bump..

your vacuum is not low at all? :confused:

your vacuum is not low at all? :confused:
I thought it was supposed to be up in the lower 20's

I cannot locate anymore vac leaks... Engine runs very well without vac advance hooked up. In park it only idles at 800r's and 600 in drive but once you plug in the vac advance it wants to die in gear again. Im guessing my vac port is wrong on my carb or something may be wrong with my vac advance.

bump

I thought it was supposed to be up in the lower 20's

12 in/hg of vacuum and up is healthy motor.