Question on cylinder compression cc503

[93blkz28]

So I have a used 100k lt-1 I slapped some ported heads on and a cc503 cam.
Wondering if my compression numbers are extremely low with this big cam?

Test was done on warm engine dry cylinders.

1# 140 psi

2# 137 psi

3# 136 psi

4# 140 psi

5# 150 psi

6# 140 psi

7# 140 psi

8# 145 psi

Thank you

[SS RRR]

Is this on a 112lsa? Those seem low, IMO, but are at least consistent. Last time I did a compression test with a car that had a 306 it was in the 180 range I want to say?

[93blkz28]

Yes the 112 lsa
I wish mine was around 180.
I'm just wondering if my low numbers are really affecting the way it's running

[Confused]

This may be a dumb question but being at altitude does that affect cranking compression numbers?Did you degree the camshaft in?

[Injuneer]

Good question. Atmospheric pressure at 6,000 feet is 11.8 psia (81 kPa), compared to 14.7 psia (101 kPa) at sea level. For any given compression ratio, the gauge pressure will be reduced as elevation increases.

And, test results will vary with engine temperature, battery strength, how far the throttle blades are open, number of crank revolutions, etc. That's why you look at the variation between the numbers to identify a problem cylinder, and generally ignore the absolute numbers.

[gmpowered]

Not all guages are created equal either, I luckily bought a cheapo compression guage that reads everything I've tried it on within spec.

I though with the cylinder s so close it looked good to me.

[93blkz28]

Yeah that engine wasn't healthy. Threw in a forged bottom end lt-1 bored .30 over.