390-sticking valve?

[SparkyGT 26]

have a 390 with a mild cam, last nite was first nite i took it for a drive, except for some moving around in the garage.

 

getting some backfires, popping, and vacuum gauge is bouncy

 

so if it is sticking any remedies

 

have heard, some ATF in the fuel might help

 

if its bent, then the fun begins

[SlimeGold 69 15]

Might just be a vacume leak somewhere. Yes..a valve stuck open ( I have never seen that unless it's bent) would cause a major leak but I would look elsewhere first, like around the intake, carb, fittings, etc.

[SparkyGT 26]

well some atf in the fuel might have done the trick, let it idle half hour, then took out for a rip, 90 mph, and a few 5000 rpm bursts, seems way better, vacuum bounces a touch but not as much.

 

will check for vacuum leaks with some water