360 block, how thin ?

Good news is, I don't "halft" to use a Magnum block and 12point per bore sonic is $80.I've heard earlier blocks are without nickle."Southwest" will let me test, before buying.$250. for a "known", bare early is worth it, to me.I will likely use partial block filler. I'm still in the air about heads. Eddy's with offset int. push rods,by me, seem like best bang/$. Thanks, Art.