Using a 4.25" stroke crankshaft in a 400 block is really all the stroke you can, or should put in a 400 block. You just run out of available compression height for the piston with any more stroke at a 9.800 deck height. With a 4.375" bore that will yield 511 cubic inches. I don't know why everyone advertises them as 512" because mathematically they are not a 512".
I've probably sold seven or eight 3.91" stroke cranks to guys building the 470" short blocks. This makes a very nice combination in my opinion. Room for rods and room to use a nice compression height piston.
Tom
I've probably sold seven or eight 3.91" stroke cranks to guys building the 470" short blocks. This makes a very nice combination in my opinion. Room for rods and room to use a nice compression height piston.
Tom