This thread is of particular interest for me--just finished testing a 461BBC Marine with a TQ-Storm and Sniper EFI/Hyper-Spark Distributor. I didn't build it or sell one part for it--just tested it. I was surprised when it produced 6psi @ 5500 rpm too considering the large 360cc rectangle port heads and Brodix single plane intake. Power was nothing to write home about but the compression ratio was supposed to be 7.5-1 and I have no reason to disbelieve that.
Have you physically looked at the pistons? An engine can still leakdown and compression test fine with missing ring lands--I've done it and seen it. If all of your pistons tops are intact then maybe you are experiencing cylinder wall distortion under load? I saw another poster ask about the dipstick not blowing out--Did it? If so-I understand If not--I don't understand why it wouldn't. J.Rob
