Why are 318's low HP and torque?

-My Dad loved the famed 318...

MY biggest question is the 2 different 318's, the LA and the A "Poly-Head" engine..... Which is longer lasting and can have more done to it between the 2? Machine work and all? I KNOW theres very little offered for the Poly engines, BUT I also know they like they're younger brother are damn near indestructible!!!!!

BUT which was the most powerful stock? AND if "lightly" built?

On the poly 318 you change the cam, heads and intake to the LA and bore it to 4.040. You now have a 340 with 318 numbers on the block. Yes it can take that big of a bore.

So don't junk those old poly 318 blocks.