ITSBACK, are you going to do the bottom end build on the 428 up front? The reason I'm asking is I've seen too many hidden problems in "good" stock engines, and there's many things that can be bad or go bad if not replaced up front. If you don't do the bottom end, then you are dealing with stock rods, stock rod bolts, and cast pistons. Many of these old engines had detonation problems that were ignored, and will have broken rings and hammered bearings.
You can do a search and see how many stock Pontiac 2-piece valves have come apart when a new cam and springs were installed. No way of telling if the valves are just below the failure threshold. They might last for another 50,000 miles with the original small cam and weak springs, but break very soon when the stress is increased. I don't have a problem running an old engine in its 'as is" condition and just driving it easy. The danger is beefing up only a few areas and hoping the remaining parts will continue to live.
I've got a set of 670's that Dave did many years ago and they are great. They are opened up to 83cc chambers and we are running a dished piston in the 4.25" stroked 428 to keep on good terms with our local 91 octane gas. Get Dave's recommendation on what he would currently recommend on chamber work and piston dishing before turning your machine shop loose on the block.
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Mick Batson
1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 Catalina Safari Wagon.
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