I have a 29 2dr sedan, i dont know to put a 337 or a 235 in it,i dont know much about the 337 flatties, just know there pricey, the motors in good shape tho,
235 is a good choice.plentiful DIFFERENT and speed equipment everywear for them. Good mileage motor geared right my 02 cents worth maybe a 5speed and a 340 to 355 8 in ford out of an old maverick or granada ***S!!!!!!!
Try the search for 337 Flatheads, There have been several threads on this engine (lots of pros & CONS). Austins Rod Shop (Ken Austin) makes manifolds for the 337 and he has built a couple of really neat cars using them-one is a '31 roadster to die for. If you're looking to be different and still have a gob of cheap torque, you can't go wrong. Throw the stock exhaust manifold away and build a set of headers and you'll save 50#.
The 235 is probably cheaper to build, but 337s are unique. Really, you can't go wrong with either. -Lee Atomic Radio www.atomicpinup.com
I liked my 337. It always started, even in winter after sitting for a year outside. Ran great, didn't overheat, kind of like a SBC without the parts availability. Everyone knows what a 235 is, but not too many have seen the big flathead. If one is available, and in good shape, really consider it. It is more expensive, and heavier, than the 235 though.