My 98 Dakota weighs 3500# 3.9 % spd, has got a best ever of 22mpg. 318's in B-bodies 20mpg average and 21.5 in my sons 66 Dart wagon when it had a 318. I'm going to do a Passion od conversion on my 65 Belvedere 9 pass. It gets 19.5 now with a automatic.

Gas milage aside, you will have to cut the torsion bar crossmember and floor pans to use the Dakota 5 spd. That was my original plans for the Belvedere but I didn't want to hack it.

Our local pick and pull sells engines complete for $119 and trannies for $55 seems you could get a much better deal than that Dakota. I just bought a nice 1 ton Van that looks and runs great for the 360 Magnum and harnesses for another project for $500. A friend of mine just passed on a $400 Dakota.