I can't say for sure on the 413's, but I have 5 of the hydraulic bellhousings/flywheel/clutch setup from the big trucks 2 of which I know came off of 361's, the other 3 I'm not sure of they were 413's or 361's. The cranks are 8 bolt, but the rear flange sticks out from the back of the block further. In order to fit that setup on my 440 I had to make a .650" spacer to clear the bellhousing. I have a picture of the back of a 361 block if anyone wants to see it.