Gold Lifetime Member
Join Date: Jan 2005
Location: 2 Dog Town in West Texas
Re: Wrong Pistons?
Check your clearances is all I can say at this point. Sounds like you are going in right direction. Using the thinner gasket you got the cr down to 13.1, I guess it improved your quench? I know about how much head milling it take for sbc but bbc is differant on chamber, much larger but if I apply that to your 14cc head differance, I would say the head was ground .80-.100. Go from there.
If the heads were cut on the exhaust side , you may notice a little differance in the head bolt hole to bolt or stud, looking sorta of cocked? Ie. bolt hole not parrallel to stud or bolt. That may give you some indication. My guess is that if the piston decks were cut , I would think that someone was trying to put more dome in the head, ie increase compression. You did not say if your rods were stock lenth or not. I have done this before by using longer rods and milling piston decks but you really need to check your clearances. I took one piston hole with piston up and bolted head on, pored hot canning wax in the plug hole and let it cool. I got a perfect mold of what my cly was, quench and all, exact but on the ragged edge.
I was using Comp CB 312 roller at the time. I had a larger 750 lift from crane that we Comp cut back to their pattern. The car ran much quicker then.
TC # 349
Zdld17:69 Z/RS,306, NOR141111, 9N554XXX, 12A, X3G, 59/59,723, AFR 195,CCC282/290HR, TKO 600, BU1122B1E Owner since Dec 1968
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