my fav for a gasser would be a 4.9l i6 they got a lot of low end torqe and im into that stuff since im pulling chevys and dodges out of ditches and back to there houses lol ans i would have to say my other one witch i jjust bought yesterday is a 302 ive heard you can build those better than a 351 but not for sure then it would have to be a 12v or 24v cummins