Hey Hotroddad your SM420 will bolt up fine to the later bell housing but will not locate properly because the later housing has a little bigger pilot hole than the early one for the 420 you can still use it but you will want to use a locater ring that adapts the 4 and 11/16th" SM420 bearing support to the 5 and 1/8th" pilot hole in the housing. Novak Conversions makes one P/N BR4 and it is only $35.00. With out a locater ring in there you risk ruining the transmission or taking out your crank bearings or both. I highly suggest you look in to this with all the great work you put in to it I would hate to see a simple thing like that ruin your day.
HevyHauler, I've got the right bellhousing. It mated up to the SM420 perfectly, just like the old one did. I'm sure it's okay.
SW Radial, that's good to know the ramshorns fit. I'd like something the flows a little better than iron manifolds though. If I can modify an old set of headers to fit without mangling them, I will. But if not, I am leaning towards one of the iron header/manifolds I've seen for sale.
We now have 6 inches of snow on the ground and still falling. So until things calm down outside, I won't be crawling under the truck much. I'm glad I got the install done before winter weather finally set in though.
