Long story short, I have a '77 mcm 898, last fall had over heating problems. Ran rough idle thru wot. water backfired out carb. Found water in LU. Replaced engine water pump and impeller. Checked engine for compression with 155-167psi. Was able to get motor to idle and ran great thru wot but still had water in LU. Replaced shift shaft bushing/seal and lower drive shaft seal in Upper. Idled great thru wot. Still had water in LU oil. Tore LU down again and found a faulty water pump lower base gasket. Replaced with new gaskets and misc o-rings. No water in LU oil but now the motor runs ROUGH, idle thru wot! The exhaust manifolds and risers are 3 years old. New plugs, wires, cap, rotor, condenser, points, alternator, and a carb rebuild last summer. Not sure where to go!!!!!!!!! I am also not needing a hair cut as I have pulled it all out and it is laying on my shop floor!!