350 compression

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Jan 8, 2010 | 5:03 AM

dannyboy11

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350 compression

hey, i havent bought a manuel yet and was wondering if anyone knew what the compression is suspose to be for a 1984 350. i tried just one cylinder and it read 90 psi good or bad?

Jan 8, 2010 | 11:27 AM

old dog

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the biggest thing you want is it to be relatively even across the Bord usually no more than a 10% difference between the cylinders .

Jan 8, 2010 | 10:06 PM

jwruss

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In my opinion 90 psi is too low, I would think that anything below 125 per cyl. would be too low for the engine to run right.

Jan 9, 2010 | 9:31 AM

maxxman04

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From: kentucky

compression volume depends on cylinder size, combustion chamber size of head, head gasket thickness, piston type etc etc.

90 does seem a little low, but what do the other cylinders read?

Jan 9, 2010 | 1:45 PM

dannyboy11

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i havent checked them all i got the motor out today so im going to strip it down and check it out. also it has been bored .30 over and flat top pistons too if that would make any difference

Jan 10, 2010 | 9:04 AM

maxxman04

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From: kentucky

in my experience, a .030 over, flat topped motor that is good should have over 130 on every cylinder. seems as though you might have rings that are shot, or a valve that's not seating right. good luck