It's a 261 with an sm420 and a vacume 2 speed rear. I plan on using the truck daily and have plans to swap the 261 for 496 cid 1/4" stroked big block. I found that Anthey street sweepers use front axles with the same six bolt pattern, spring size and spacing. these axles have modern 15" disc brakes and a 6000# rating. I also plan on gitting rid of the hydovac brake booster in favor of late modle hydoboost unit.
