67 el camino Valve problem?

[91Caprice9c1]

Hey folks,

I've got a 1967 ElCamino with a 327 and a holley 4-barrel. It's running very poorly. It idles, but very roughly, when in park the engine can be felt kicking on a regular basis. When in Drive the car feels like its on the brink of stalling, but it stays running, and has a HUGE loss for power. When in Park, a backfire will be sent through the intake with a sharp stomp on the gas, but it will rev with a slower approach on the accelerator. My vacuum guage shows an erractic needle between 10" and 20"hg at idle, and the same reading give or take a few "'s as you rev the engine. Compression is good, i cleaned some pretty heavily corroded contacts on the rotor&cap, new wires, new spark plugs (and gapped to .035"spec). Does anybody have any ideas?

Thanks again,
Matt

[tom3]

That sure sounds like the firing order is out of whack, plug wires on wrong. Second guess would be a pretty major vacuum leak, vacuum hose broken off somewhere or a leak at the base of the carb. Might try adjusting the idle mixture screws on the carb for more fuel at idle.

[jveik]

lol my 350 in my truck started acting like that before i started restoration... it had a definate valvetrain problem, as i saw when i took off the cylinder heads and one exhaust valve was burned out and probably half the valves werent even seated all the way!!! it was really thick with carbon deposits too and the block had scratches in the cylinder bores lol...

[91Caprice9c1]

thanks for the input guys. i've got it running better (though i don't know what i did to do so). I removed the carb, cleaned it out real well and reassembled it with fresh gaskets, then stuck it back on the intake manifold with a fresh mounting gasket. although it's running a lot stronger, it still gets rough at idle intermittently, and intermittently will backfire though the intake with a sharp rev in park. I'm leaning towards a vacuum leak...

[dmbrisket 51]

whats your base timeing at? and 10" is a low number for a moter at idel