A lotta the GMC's used V6's. Yes. V6's. BIG V6's. Like well into the 400 ci range. When I go back home this August I may have to steal an old book from my dad with information on these old engines. GMC had a thing for the V6 for some reason. The biggest they built was a V-12, which was two of those 6 cylinders stuck back to back. It's max RPM was like 3200. 8) Gas mileage on that was probably 2 gallons per mile.
Oooh! Webpage! Check these stats out!
http://www.6066gmcguy.org/EngineData.htm
478 CI V6. 637 V8. 702 V12. I've seen a couple of these. Unfortunately, they won't fit in the smaller trucks.
