Heavens to Murgatroyd, if you are going with an C-10 chassis & rear end, why would you want to drop a SM420 in it? Or a 235 for that matter...
It's not a '48 1 ton after that swap, so no point in keeping the SM420 or the 235. I don't think they built a 235 in 1974 either.... set the bourbon down and get yourself a modern engine and tranny; that's way too much work to put into a mod project, and then end up keeping that cranky, old drivetrain!
