I have a '71 2-bbl 350 with stock intake, carbs, and heads. My dad and I believe we hear a lifter rattling and he (and several other 'car people') thinks that the valves aren't opening in at least one cylinder (the car seems to lack power, even for a 2-bbl). My car diesels a lot in warm weather, no matter if I'm running 89 or 93 octane. I've noticed lately that the paint on the intake above the inner four cylinders is flaking off or looks charred-as if it's running to hot and lean in those but fine (and I'm not sure, I'd have to pull the plugs to check, but maybe even rich) on the outer cylinders. If the valves aren't opening in a cylinder, will this cause dieseling and this inner-cylinder heat? Or do I also have a carburetion issue I need to check into? Thanks if anyone has any helps or steps I need to take to resolve all of this.

A compression test would be a good place to start. Follow that by removing both valve covers, crank the engine over, and observe the operation of each rocker arm. Be sure to disable the ignition system before you start any of this. You want to make sure each rocker arm is moving up and down approximately the same amount. If you observe one that's not moving, or is not moving as much as the others, the problem could be anything from a wiped cam lobe to a bent pushrod or a collapsed lifter.

Dieseling, or run-on, is usually caused by incorrect timing or incorrect idle speed setting on the carb. A dead cylinder would not cause this. The probelm of a hot running cylinder is more than likely going to be due to a vacuum leak somewhere, either at the intake to head mating surface, or one of the hoses or fittings in the intake.

Badly worn exhaust lobes will cause a pop out of the carb and intake lobes will cause a pop out of the pipes.

Originally posted by soccerguy045:
I've noticed lately that the paint on the intake above the inner four cylinders is flaking off or looks charred-as if it's running to hot and lean in those but fine (and I'm not sure, I'd have to pull the plugs to check, but maybe even rich) on the outer cylinders.Check that the hear riser valve is opening. If it's closed the exhaust from the right side will be forced through the intake manifold and out the left manifold. It wouldn't run very well if this is the case.