The truck had a 235 in it when I bought it. The flywheel for that was 4 bolt for 6 volt. When I found the 270 I had the 6 bolt pattern drilled into that flywheel. The clutch may have been original. It was 9 inch. I bought the flywheel that I am using now from a member of oldgmctrucks.com. It is 6 bolt for 12 volt. The listing at my favorite FLAPS showed a 10 inch clutch being original, but his part number had been succeeded by the 10-1/2 inch clutch that I have now.
When I had the current flywheel re-surfaced I discovered it to be very ugly with spider web cracks all around. If I can find the right flywheel, then I may buy a new aftermarket one and get the clutch that fits that.
1950 GMC 100 Panel Truck, 1958 270, 3-spd Saginaw with BW OD, 3.73 12 Bolt Differential from a 1966 C10, Front Disc Brakes Bought it in pieces 9-1976, driving since 6-1978 Follow in the DITY | 
