How many hours does everybody think before rebuild on 502 mags?? Motors were used very mild not in a performance boat

1000

Get a compression and leak down test done. That will give yousome useful info on what you may need done.

For reference, what are good compression numbers?

Cole,

I am no engine guru so hopefully some of them will respond. From what I understand as long as the numbers are not to low, the important part is having them about the same for all 8 cylinders. I think 150 is a good number for a new(er) engine. Mine were on the low side (115-120) on some of my cylinders on my engines that were supercharged. I had my engine rebuilt (top and bottem end).