The flywheel bolts are the same as for Chevy small block V-8,dime a dozen.The head bolts can be found for $2.25 each at Mcmaster Carr industrial supply online. They have many sizes of grade 9 special bolts.On a 235-261, a guy I know used Ford 351 Cleveland rod bolts,grind the side of the oval shaped head,use a washer under the nut,use those bolts when you have the rods sized at the machine shop.The mains? precision part, the grade 9 won't work unless you machine the bolt true like a dedicated main bearing bolt.
