The big truck (Industrial) 375 and 413 were 12 port. They came with dual carbs and dual exhaust. Mine has a special "high compression head" maybe 7.5 or 8 to one with a tag that says "use only with special fuel or at high altitude". If I had a 375 I could revive the Bonneville toy plan. Or at least a 375 crank. There is a thread on here somewhere about the recovery of that big engine. It used to have pictures attached.
