I have been reading thru some posts and I see some people talking about clearances in some people's engine's being way to tight? I assume it is bore clearances? Why do some people say a jetboat is different and what shold they be?
     Thanks

Hmm so my 454 just had a fresh .060 I do have a set of used .060 manley pistons I guess it would be better to use those instead of a new "tight" setup??

as rod had mentioned the cyl get hot but actually its the pistons that get hot and swell, the block does'nt expand due to the open cooling sys that we use so as a rule of thumb 1-3 thous on the bore. bearings are'nt as picky i go with 1 thou for every inch of journal so if you have 3 inch mains that would be 3 thou clearance, these are just general guidlines you or your engine builder will have to make your own descions based on what you want.  hope this helps
ralph