Back in the dark ages when I was learning to build engines, a lot of my experience was gained by watching my father build flathead Ford round trackers. If you think a stovebolt is a primitive design, then the old flatty had to be downright stone age! A V8 engine with only three main bearings- - - -and the valves, intake and exhaust system all in the block! One thing race-modified flatheads with long stroke crankshafts were prone to do was break crankshafts- - - -they would twist themselves in two at the center main bearing. It was a pretty common practice to install a "billet" main bearing cap on the center position- - - -a piece of solid steel plate machined to duplicate the usual cast iron main bearing cap.
On the stroker stovebolt engines I've got on the drawing board, I'm considering doing the same kind of thing for the two center main bearing caps. They will be machined to use Chevy small block 400 mains, and the only place a spacer will be needed will be in the upper half of those two bearings to take up the extra space between the main bearing and the block. Since the front and rear main caps are shaped to accommodate the timing cover and the rear seal, they will need to remain original. The billet caps in the center will make the assembly more rigid, and help the main bearing clearance stay at a minimum- - - -maybe even using four bolts instead of two. I'll probably also use studs instead of bolts to attach the main bearing caps.
Jerry
