I think the 340 is the best small block engine ever made during the muscle era - sorry Chevy guys!
I've owned three 340 powered Mopars over the years and I was always surprised at how well they ran given their inherient design handicaps. Handicaps? Yeah, the little 340 has a few. With only four head-bolts per cylinder we use to ocassionally have cylinder sealing problems when running really big compression. That same four head-bolt per cylinder arrangement created those ill-flowing "porkchop" shaped exhaust ports on the center two cylinders too (thank goodness for the W series heads). Then there is that screwy valve train geometry that has all sorts of angles between the lifter, pushrod, and rocker arm - nothing lines up at all! I read somewhere that when Mother Mopar designed the "new" LA engine in "64 they kept the same cam lobe separation angles from the "old" poly-headed A engine and that's why the lifters don't line up with the pushrods and hence the pushrods not lining up with the rocker arms.
When they were using the small block for Pro-Stock in '79 and '80 they would literally have to cut the lifter valley out of the engine, weld it back in at an angle that aligned the lifters with the pushrods, and then use a custom cam with the new lobe separation angles. Pretty extreme modifications but necessary to correct that goofy valve train geometry.
Don't get me wrong, I love the 340, and I ran with some guys who could make their 340's screaming giant killers. It's just that "back in the day" the 340 was fighting with a design handicap and I often wondered how much better that engine could have been with a little better engineering from Ma Mopar.
