For what it's worth I just sold off one of my '54 half tons which had the 54 261 with Corvette cam and dual exhaust. I was impressed with the pull on the freeway when some onramp jerk would try to merge into my fender; I could pass with ease. Only problem was the rear end gears kept me limited. The slow lane is where jerks often can be found merging!. The engine looked very original and had lots of torque. I did not do the swap but acquired it that way. I am swapping a 235 into my other one now and it seems fairly easy, as long as you've got the correct parts!