8BA Compression Leaks

I am in the process of pressure testing the left bank of my 8BA with the head on, but no intake or exhaust manifolds. With each cylinder at around TDC, I am applying about 80 PSI through the plug hole and looking for leaks into the coolant. I found that at 50 ft lbs all the cylinders leaked. Air bubbled out the upper rad hose goose neck, or the coolant (water) rose up and ran out the top. At 60 ft lbs they seem to be OK. The head gasket is a “Best” composite grey fiber with the metal fire ring. Note that I am using ARP studs rather than the 8BA bolts. This has raised some questions which some of you may have answers to:
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1- Why did the torque specs change from 50-60 ft lbs with studs and nuts to 65-70 lbs with bolts?
2- Was it because the coarser threads on the bolts, need more torque to get the same pressure on the head?
3- Did 8BA heads change needing a new spec
4- Can I safely torque the studs to 70 ft lbs without damage to the heads or gasket? I am using stock cast iron heads.
5- I am also hearing air coming out both the intake and exhaust valve ports on all 4 cylinders during the tests. Putting my hand over the ports quickly builds up pressure behind it. Is this normal? The valves are new, the gaps are OK and the seats have all been ground at a machine shop. I don’t think they were lapped however.
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Al

 

There are two things to do here. Put it together and drive it, or take out the valves and lap them correctly. If all the valves leak, the guy doing the grinding may have tweeked the angles on the seats or the valves. I would double check that first.

 

You torque arp studs less because they ha e less stretch because they are a harder material. Bolts have to stretch a lot more to get the clamping power.