ok, gas burner, for now the best i've had is my 300 I6. torquey engine, even at stock, plenty of aftermarket parts for it, and can be built to do things that most V8's can do, and at 2 less cylinders mind you! other than that (for gassers) i'd pick the 460. sure it's a fish, but u never feel the load behind you, no matter how big it is...
for diesels, i'm gonna go w/ the cummins 5.9 12 valve. wat can i say? i'm a sucker for 6 cylinders! next up after that is the 7.3 stroker!
I'm torn on the gas burners. It's between the 427 (side oiler) and the 428 cobra jet. Now, as far as diesel is concerned, I've only dealt with one. That would be my 6.0 Powerstroke, and I couldn't be happier!!
My favorite out of the several old pickups I've had is the 390. I'm not much of a motor-head though... as long as it runs decent, sounds good, and gets me from A to B without any problem, I'm a happy camper.
The 351CJ that was in my '72 Mach I for sure. 4 bolt main with the 4V heads. I added a torker intake with a holley 600, cyclone headers, crane fireball cam, and an accell dual point. One hard running motor!
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