I'm not trying to scare anybody.
By the way, mine was .040" over on the bore.
All the performance books recomend using a torque plate on the block with whatever head gasket you plan on running.
The torque plates became a big deal when the 400 came out. I don't think they were used before that on a chevy, but it was found for racing that the torque plates were pretty much neccessity on a 400 and a good idea for any engine. I've heard of people doing valve jobs on heads with a torque plate on the head...
Now, a leakdown guage has a jet the air goes through then it goes to the cylinder so you are measuring a percent of leakage OF THAT SIZE JET. It isn't the most accurate measure of the complete compression loss when the engine is running, I think a blow by measurement is better at that. BUT the leakdown test does give a measurement of relative loss one engine to another.
I measured %65 loss on my cold engine, it all was going out past the rings, I could hear the air in the crankcase blowing. I did it on an engine stand when the engine was out. The rebuilder had welded the front throw on the cast crank so the crank of course broke as soon as the warranty was over!
I didn't see a lot of blow by on this engine, it ran fairly well till it started knocking up front. I would have guessed the leak down was less than %10 by the way it ran.
I'm not saying the engine will not run, but there would probably be a measureable loss in the leak down dept. I'd like to know what the horsepower loss of that would be.
Check my web page for First Gen Camaro suspension info:
David's Motorsports page
First Gen Suspension Page
67 RS 327 original owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer