i have a 75 400 that i'm working on trying to find info on correct modern day spark plug to use and if a 520 chain is correct . thanks
hi edward. i use a ngk B8HS in mine. some guys use B9HS but the 8's have worked for me. to me 520 chain is preferable but you have to make sure that you have 520 sprockets to match. back in the day they ran 530. chicago jerry