My '40 block is original bore but measured about .020 out at the worst place. I have a good Ford crank but two good 4" Mercs so would like to use one of those with 8BA rods. I have some .030 pistons but those are 3.1875 rather than the 3.0625.I do not want to just to a 3.1875 bore though that would be super cheap to do. I'll be doing the bores myself and would rather not sonic test just to jump many bore sizes. I am not finding a source for the early pistons(O/S or not) for the 4" stroke. Is this a special order only? Also, isn't it true that I can insert the piston/rods from below since the 8BA big ends won't fit the smaller bore? Thanks in advance, D
That's one of the advantages of a 3 3/16" bore. I'm really only familiar with 8BA's, but I have never had a problem going 1/8" over. I would think the 221's would be even better, given they are 24 studs. The 21 stud blocks, I don't know.
I checked those sites but 3.1875 is the standard. I suppose the obvious issue is the small early bore which was never mixed from the factory with the later 4” crank. I guess that means custom to me. D
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