Hi folks I thought I'd get the ball rolling with my favorite car the 635CSi. I'm in the early stages of building up a circuit 635. Currently I have an 86 5speed road goer and a 1981 E12 based 635CSi shell that will receive an S38B35 engine I have in a crate. In the shed there's also an M90 engine. From what I understand so far, and please chime in with any advice here, is the M90 crank will stroke my S38 out to about 3.9lt. There's no doubt a lot more to it such as piston height etc. As I said any advice would be apeciated. Coupled is a dogleg and back further to an early sideloader "big diff." Anyways thats the running gear to date. So lets have a look at some 635CSi race cars.