Quote:
Originally Posted by JL8Jeff
Hey John, do the longer rods require any kind of modifications to the bottom of the bore area to make sure they don't contact the sides of the block? Since you are changing the geometry of the rod angle with it being longer is there any chance of contact?
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as was said about clearence --- you are thinking about the big end of the rod and the issue is the small end -- Think of it this way - its longer at the small end - and the angle at the crank as it aproaches the block jug bottom is actualy flattened a little but not much -- the clearence problen comes in in a 383 or a 400 motor combo in two places - first with alloy rods the block has to be machined for sure in 2 spots barrel base and the oil pan rail -- H beam rods for the most part will need a little feness - you want at least .060 rod bolt to barrell / pan rail - but most times you will need what they call a small bace circle cam -- the cam bottom or base circle is to big and can contact the rod bolt as well - at the point of valve lobe - ( they custom grind the entire cam circle smaller with out changing the overall size of the cam ) real pain to check -- and this is another example of core shift issues in the block as well -- you will have to check all the lobes to rod distance - and .060 is the spec it has been determined that the rod grows .040 so you will be ok at .060 - and sometimes you will have to get another block because the internal core is up and over in such a way you can not get the clearence - even with the smaller cam base circle - and i have been their more than once i hope i have not comfused anyone just i do this almost all the time and its like i live it if you know what i mean -- if i have not answered it so you get it let me know i will re do it -- jz