400 Sonic Test Results

slimjim said
Ok, I’ve been trying to find some sort of guidance regarding cylinder wall thickness. Unfortunately, there’s so much clutter regarding the subject that it’s hard to pinpoint exact figures. I’ve read that .160 is required for anything over 500hp. Then I dug into another article and read that the .160 is only critical on the main thrust side. I’ve currently got the block in the shop waiting for direction. Block needs a .02 overbore to clean up. What do you think?

Block is a ‘71 230 casting with the thick mains (Aka the Cold Weather Block)

*Plan is to build a 500-600hp stroker*

View attachment 1715600441

That block will be okay. It isn't the greatest ever but it isn't the worst you could run into. Should be fine for a 600 hp engine. You can do the 0.020 bore now and then the block should last a long time since you'll be able to redo it one more time. If you take it to 4.375 now then it might be used up. Of course, it could take 50 years of driving before you used it up so maybe don't worry about it.