You should ask IQ52, for those numbers it just makes sense to use something at 2'' or bigger...i would think much diff between the 1.78 and 1.88....its just +.050
Is this a maxed out version? IMO yes.
The runner is just smaller cast inside, the outside parameter is almost like a 360. same push rod location, divider wall, just more to grind out 'except the guide'. The main difference is the guide, floor, ssr.
318 port floors are flatter.
take a 340 and put a set heads on like IQ52's in his example...then snap the throttle and tell us what u think....that is if the port is still smaller..lol
I will do a thread with 2.02's put into the 675's i have in the thread and report back.
Thing to remember is that a ported 340/360 head has better low lift numbers still...so where do you really end up better?
btw, IQ52..what port volume do you end up with?