I just did the same thing to my 58 GMC. You'll need to find a bellhousing from a V8 version, I believe 56 up to about late 60's someone will correct me here. Then you'll need the flywheel from the same source. I'm using flywheel and 11" clutch for a 67 Chevy. The clutch linkage can be had from classic parts and lmc. I've replaced all my linkage and have usable spares if you need them, just let me know.
Was your truck originally a 3 spd truck or was it one of the hydamatic trucks. If it was the 3spd truck it will already have the clutch pedal parts in the cab.
I'm coming down home stretch with mine now and hope to have it running soon. This is a conversion I've done several times, but 30 years ago. I can't wait to hit the road with mine so good luck with yours. Larry
