Since this got bumped, I'd like to point out that Boosted E21 is way off about the engine. It is a regular V8. The one in his picture is the Glas V8, which is not a BMW engine. The 507 had an updated 3.2L version of the 502/503 overhead valve V8 with a regular style cast alloy block. This motor was used in the 501, 502, 503, 507, and 3200CS. The Glas engine pictured above was never used in any proper BMW. There were a few Glas BMWs that had that motor in them, but that car was nothing more than a BMW badged Glas. The engine in the picture above was an overhead cam V8 that debuted in 1966 (7 years after 507 production ended. This one below is the BMW V8
Thanks for saving me that research, Paul! I knew that, but I didn't want to have to go digging up a picture of a 507 block to prove it. I wanted to do the simple search for something else I knew existed: the most outrageous piston engine transplant ever done in an Isetta. All you gotta do is Google "Isetta Allison"