1968 383 compression test

[Al]

After having replaced the old 906 iron heads with the Eddy performer rpm heads (84CC) and the stock cam with the Voodoo 60303, I did a compression test. All cylinders show a compression of 175-180 psi. I'm positively surprised, I didn't expect that much pressure especially for a 40 year old 383 with 9.5-1 compression ratio. Is this a normal figure for 9.5 compression?  

Al

[frederick]

Very good result I'd say.
I got 150 cold with a 383, Voodoo 60302, stealth heads milled to 75cc's and 9.7 compression.
Haven't tested hot yet.

How's your piston to valve clearance?
Mine was right at the recommended minimum of 0.080" for the intake valve.

[Al]

Very good result I'd say.
I got 150 cold with a 383, Voodoo 60302, stealth heads milled to 75cc's and 9.7 compression.
Haven't tested hot yet.

How's your piston to valve clearance?
Mine was right at the recommended minimum of 0.080" for the intake valve.

Mine were also taken cold (late summer temperatures, without prior warming of the engine, I didn't want to burn myself on the headers lol). I didn't check the ptv clearance. The pistons were down .007 in the hole. I degreed the cam and installed it on a 104 deg. intake centerline, that was as close as I could get to the recommended 106 deg. Yes the idle has a slight lope.

Al

[firefighter3931]

That is perfect compression for pump gas and aluminum heads.  The cam (intake valve closing event) will also influence the cranking compression so I'd say the combo is very well matched. Someone did their homework 


Ron

[Al]

That is perfect compression for pump gas and aluminum heads.  The cam (intake valve closing event) will also influence the cranking compression so I'd say the combo is very well matched. Someone did their homework 


Ron

Yes Ron thanks to you and to your valuable advice. I'm very happy with the combination and the results. 
Al