I agree this sounds more like the timeing chain has sliped .
I am not sure what carb was used on your model. but on my 37 with a 216 it has a Carter W1 on it

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37 Chevy 1/2 Ton


37 Chevy 1/2 Ton
86 Chevy Blazer
98 Drudge 24 valve Cummins
One worn out Timberjack