Thanks for the info Tim.
I am 6 volt but this engine cam with a 12V flywheel big clutch arrangement that looks fairly fresh, so dont know if I will make the change.
Are the balancers interchangeable and both cranks internally balanced?
With the dowel in the flush position, I suppose I do not need to connect the big oil ports together with a large hose, is there really any advantage to running it in the full filtering mode. Did GM leave all there trucks leaving the assembly line in bypass mode?

Steve

1953 Chevrolet 3100
261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY Gallery
Video of the 261 running

1964 GMC 1000
305 Big Block V6, sm420, the next cab off restoration