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302 Engine


Supporting Member
Supporting Member
Found a 1975 302 engine and have had it gone over and making it ready for the "T". Running into little things and have managed to get thru most of them, but am having a hard time determining the size and thread of the four bolts that hold the water pump pulley. I have seen 5/16-20 and 5/16-24 and 8mm X 1.25. Having even harder time finding any of these bolts. Can someone tell me what the correct thread is? It seems a 5/16-20 goes in easy enough, but I can only find it 1" long ... too long.

Any help appreciated. :confused:
I usually use a tap to find thread pitch. i also Use a tap to chase the threads to clean them out before I put a bolt in. Just a technique I use. The bolts should be easy enough to find at any parts/hardware store but McMaster-Carr is always a source when all else fails.
It won't be metric, too far back for that. I think 5/16 fine thread, 24 threads per inch, if I remember correctly. You can go to your local Ace Hardware and in their bolt section they will have these in lengths from 1/2 all the way up, and even in grade 8. Grade 5 will be strong enough, but I use grade 8 on almost everything just because.


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