It's a simple matter of measuring everything- - - - -intake valve seating, piston-to-deck clearance, crankshaft journal dimensions, connecting rod specs, cam timing, pushrod length, and about half a dozen less critical dimensions that can stack up to either work well together- - - -or not. The newest stovebolt six engines are over 50 years old, and the basic design goes back to the late 1930s. There's no telling how much they've been whittled on during that time- - - -some have been "rebuilt" several times, so the specifications our resident number crunchers like to quote as if they came down from Mt. Sinai chiseled in stone are SWAGs at best. Just like Sun Electric Co. used to say- - - - -"We Test, Not Guess!"
Jerry
