Its a GMC 637 cid 60 degree V8 engine based on the old GMC Big Block V6 engines. iT replaced the Twin-Six V12 in the engine line up. It came in both diesel & gas models. many got use in boats. Gas version had 275 hp & 560 lbs. ft of Torque.
More info can be found on my site, but not much more, and no photos.
