Mine is a 1976 Chevrolet C30 Crew cab with a 6.2 diesel and Muncie 4 speed.
Only modifications I have made were the '85 6.2 that I dropped in to replace the 350, and a Dana 70 HD 4:10 rear axle to replace the lighter duty GM 3.73. I also built a 9'3"x8' flatbed to replace the old, smaller one it came with.
Future plans are to do a complete frame up rebuild, drop in an auto tranny (which it originally had), and put in an '89 turbo 6.2 low compression propane injected diesel to boost my total horses to about 350. - Mr Diesel
'76 C30 Crew 6.2