I have a 1938 Pontiac 4 door , survivor, When an errant rod from the flathead 6 went through the crankcase. I swapped in a OHC 6 Sprint from a 1968 Firebird, backed up with 200 4R Buick (BOP), Nice fit! Came up a little short for an engine mounted fan. Car remains essentially stock (but 12V, 605 PS box). I like it but would like better brakes without major suspension mods. Fellow NNVI inliner has OHC 6 in a 50's GMC. Have not torn down the flathead to see why it failed. Externals suggest the engine was attended to during resto by PO. Am disposing of items from my "pull" but useable engine items not yet sold. I Have photos of Sprint swap if interested,