I recently got a couple 49-53 flatheads. One is a Ford and the other a Mercury. I plan to use the Merc crank in which ever block I use. The Ford engine looks pretty good inside. I just got the Merc and haven't gotten it apart yet. The Ford engine had this tag on the front. So, it has been rebuilt at some point. .040, .010, .010. Kind'a neat. "Authentic Ford Reconditioned" (I think it says). I've been doing some reading and if I'm correct, the internals should be the same between the Ford and Merc, save for the stroke. First question: Are the pistons the same? I mean as far as pin height, etc. I've read about using earlier (24 stud) heads to get the center water outlet look on the late blocks. Second question: Aside from the distributor hold down clamp, are there any other advantages/disadvantages in doing this? Last question (for now) I have a vintage Sharp two carb intake. I have another 48 flathead with a carb and the Merc engine has a carb. Would these be the same (to use on this manifold)? I haven't had time to really look at them yet. This car (see my avatar) has been begging me for another flathead for years and I'm finally gonna do it.