I have a 50 flathead that I'm trying to turnover by hand to make sure it isn't stuck. I don't have the crankshaft bolt and I am hoping someone knows the correct bolt size and thread.

Thanks all.

 

I'll measure mine tomorrow but IIRC it is 5/8-18 X 1 1/2"

Yes it is 5/8"-18 NF and 1 1/2" May be a little long. Mine is 1" but that is a little short.

 

Perfect! Thanks fixnair! I got a 1 1/4 length, although not quite sure if it is correct as I still need to locate a pulley. Used a nut as a spacer and got the thing to turn over, so glad to know it isn't stuck. Now just a sticky valve to fix and i should be good!

Pain to find the bolt... went to 4 different places before finding the single bolt to buy. Without you taking the time to check yours I never would've found it as I wouldn't have known exactly what I was looking for. So happy there are people like you on this forum! Thanks again.