383 compression test.

[SandDiesel]

Just acquired a 65 Belvedere with a 67 383 and 516 heads. Assuming it's stock what's an acceptable psi range and what should a fresh stock rebuild reach for psi? The seller inherited the car and believes the motor is modified but just looking for a baseline I guess.

 

[Meep-Meep]

I'm thinking 150 PSI is about right.

 

[SandDiesel]

Thanks! Will test it this weekend.

 

[Manifold]

I don't know the details on my 383 with 516 heads (other than ~25,000 on rebuild), but it was ~135 psi dry and ~150 psi wet.

 

[Cranky]

I don't know the details on my 383 with 516 heads (other than ~25,000 on rebuild), but it was ~135 psi dry and ~150 psi wet.

Was the engine warmed up and had the throttle wide open when you tested it?

 

[Manifold]

Was the engine warmed up and had the throttle wide open when you tested it?

Engine cold and no carb installed. Is there a general/ballpark number of increase in the readings one can expect between cold and warmed up?

 

[Cranky]

Tested one once like that...cold then hot but it was in such bad shape, it really didn't help much until I threw in some oil in the plug holes.That told me the rings were shot....

 

[1badgtx]

Crankys right about doing a hot test...Cold is a different story as far as true compression..
Petty Blue 67 GTX