What he has there is probably a 391 Truck block engine. These had the reinforced webbing around the mains along with extra thick cylinder walls for over boring. As always though you want to make sure the engine is sonic checked beforehand. George Anderson, by the way, told me as long as you don't mind carrying around 30 extra pounds the truck blocks are good to build around - if you find one. As he was saying they are becoming hard to find. Go figure, Sid-Oilers and hard to find 391 truck blocks!
