Why are 318's low HP and torque?
Oh and the 318 has same stroke as a 340 and same rod length just bore is different.
Well, look
At the risk of .........................
Let's look at the several Chivvy small block combos
283, 301 (we used to call 'em, GM "renamed" it 302!!)
327 (We'll just ignore the 307)
and 350
Mopar 273/318/ 340 all the same stroke at 3.31"
Chivy 265- 283 / 302 stroke is 3"
327 stroke is unique at 3.25 stroke
350 is 3.48 stroke
302, 327, 350, are all 4" bore
So a 318 is not all that much different from a 327, which were pretty much great engines "in their day."
Only difference is, that GM BUILT them with compression, heads, cam, etc, instead of (Mopar) putting them out as a deduned 2bbl family sedan mover
(And don't forget, GM pretty much did the same thing with the 307 as Ma did with 318's)
But if you want to start preaching "bore to stroke" ratio, what about the 305 TA engines which were de-stroked 340's and therefore had a LARGER bore than a 318, with a shorter stroke?
I think the real answer was in the first few posts --these engines never enjoyed decent compression, cam, or intake and exhaust.
Don't forget most 318's were factory single exhaust, with WORSE exhaust manifolds than the 340/ 360s
Many came with smaller ports, and certainly "undecent" 2bbl carb and intake
Finish it all off with low compression and a camshaft which only accidently opens the valves, and you have..................
