got my engine

[48find]

OK, so i picked up the engine im hoping to run in my 48 GMC pickup but its a completly different route from what everyone always takes. I'm a fan of the oldsmobile big blocks so i snagged up a 66 oldsmobile 425 Big Block and trans that supposedly runs. these engines are a shorter stroke and make amazing torque factory specs for the engine was 385HP and 495 ftlbs of torque so now my question is this engine is almost 26" outside valve cover to outside valve cover they are super fat engines... is this gonna fit? also i know the engine needs a decent rear end to support the power any ideas that would fit the 48?