Compression readings

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The cylinder heads need to be surfaced the same amount.
If not your intake will never seal for very long, I don't care how much sealer is put on, it won't seal.
I'd be interested to know what pistons and heads on it to register such high cranking #'s.
I just can't see those numbers with an open chamber head.
Look for a leaking intake manifold causing the rough idle.
Flat top forged pistons as far as I know.....906 heads ......
 
Have u confirmed compression with another tester? Seems high for that combination of parts unless the piston is sticking out of the bore about .060. Kim
 
Again, no air should leak past the valves. The valves are either bent or the seats were not prepared properly. Take the heads off and shine a light in the port. If you see it past the valve you have a problem.
 
Again, no air should leak past the valves. The valves are either bent or the seats were not prepared properly. Take the heads off and shine a light in the port. If you see it past the valve you have a problem.
Yes this ^^^^^ for like the FOURTH time now.

ZERO air, as in NONE AT ALL should be getting past the valves. It's not a case of "a little is ok". NONE, ZERO, ZILCH, NADA, NUTHIN.
 
Yes this ^^^^^ for like the FOURTH time now.

ZERO air, as in NONE AT ALL should be getting past the valves. It's not a case of "a little is ok". NONE, ZERO, ZILCH, NADA, NUTHIN.
You ever say something about me beating my head against a wall?

All together now.....

One....

Two....

Three.....

BAM!!!!!
 
Again, no air should leak past the valves. The valves are either bent or the seats were not prepared properly. Take the heads off and shine a light in the port. If you see it past the valve you have a problem.
I'm going to get beat up for saying this. Yes in theory you should not have anything leaking past the valves. But I see motors that leak a little, run fine and still have good power. Sometimes a leaky valve can be stopped or reduced by lightly tapping the valve with a hammer. And yes sometimes a leaking valve or valves can be a problem. A big problem. I have found it's not always cut and dried a little leaking (while not the ideal situation) might not be the problem at hand. Then again it might be.
 
So most mopars very in deck height.
One side can be taller then the other.
If the block was not decked couldn't that change the cr from one side to the next ?
If the pistons are closer to the top because one side is shorter maybe that could be the difference?
 
I had a 70. 340 I re ringed back in the early 80s. Did a compression test after 5000 miles. 1 side had 165 lbs on all 4. The other side had 160 lbs on all 4. The block wasn’t surfaced or the heads. Kim
 
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