I am guessing the pal nuts came about for Farmer Bob who ran the engine until it knocked like a drunk tap dancer. The pal nuts would keep nuts on even after the worn away Babbitt created slack thus eliminating the stretch in the rod bolts (which would normally be enough to keep the nuts tight).
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
