Ive got an 85 blazer 350. Still trying to decide if im going to use this engine to swap out my tired old L03...anyways, its got about 50,000 miles on it with 160 psi on the compression test. Is this good? What is optimal?

 

For whatever it's worth my brand spanking new 4.3 ( or 3/4 350 ) was 145 on all 6 when I checked it after 2500 miles

 

Is that 160 on every cylinder? A more important test would be to check all the cylinders (if you haven't) and compare.

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82 camaro--original steering wheel, brake/gas pedals, seats--everything else modified
82camaro

 

Seems reasonable to me. If within about 10 psi between cylinders, it's probably OK.

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"So many Mustangs, so little time..."
ICON Motorsports

 

Remember, camshafts also have a great effect on the cylinder psi. A larger cam with overlap will bleed pressure off and give a lower reading than a short duration/wide LSA cam.

All comments regarding "balance" between cylinders is correct and of a greater concern than the pressure itself.

Another useful test is leak down. That measures how well the cylinder holds the pressure.