To me it comes down to look, style, reliability, aesthetics, etc.. There are plenty of well running B motors around - they've actually made a resurgence in the HotRod world in the last 10 years. As Michael mentioned, if you're thinking of a STOCK 32 engine, the B is actually a better engine than the 32 V8 (for a multitude of reasons). If you're talking about running a later V8, then putting any 39 - 48 flathead in the car is the way I'd go (as I like V8's).
The one thing I'd recommend is that you consider the COMPLETE PACKAGE and what your goals are?
1) Do you want a 100% stock 32 . . . then your choices are limited to what was available from the factory. There are plenty of folks on this site that know the intimate details of dang near every component, nut and bolt for a 32 - given the various builds and dates.
2) Do you intend to "update" the car to drive it at modern highway speeds - at 60+ miles per hour? If the answer is "yes", then there is a LOT more to think about than just the engine.
Think About Everything: You really have to think about the whole drive train -- to include shocks, brakes, etc.. Mechanical brakes at 70 mph, with bias ply tires, no sway bars, sub-optimal shocks, etc - is a somewhat dangerous situation. These systems were designed when there were no interstate highways - most folks rarely (if ever) had their cars over 55 mph. Most of the folks in my family who had them back in the day, drove them on 2 lane roads at under 50 mph.
Highway speeds: While the stock brakes might work really well the first couple times you use them . . . how about going down a long hill and seeing how they fade with repeated usage at 60+ mph?
My main point is that you need to think about the end-game first (including budget and time), in making many of these important choices. It starts with goals and expectations - then you move on from there.
Best of luck!
B&S
