Ported Slant 6 head
I have my 170 for that. I got plans. lol
Well, it's really none of my business, but the virtually 33-percent larger swept volume of a 225 gives it an almost insurmountable advantage over a 170 when it comes to making power, (especially since the same head is used for both,) so if you really want to go fast, though it's possible to do it with a 170, it's a whole lot easier (and, cheaper,) with a 225.
It's a fact that the 170 has a storied history of runaway success in Class racing, and the Daytona Compact Race speaks volumes about how well a 170 can run. It has high RPM capability like no other, and the cylinder head was designed for it. In a class where the vehicle-weight is decided by a pounds-per-cubic-inch formula, there's just no better size to run; the 170 will ALWAYS trounce the 225's.
There's no question about that.
But, in the world of street or bracket competition, where TOTAL OUTPUT is the deciding factor, the old adage of "there's no replacement for displacement" holds true.
Different people build different engines for different reasons.
If listening to an 8,000 rpm song is what trips your trigger, then the 170's for you, because they have that capability! In spades!!!:cheers: I'm sure a turbocharged 170 running 25 pounds of boost at that kind of RPM would make tons of power.... and probably live.
But, if you just want a LOT of power from a slant 6 the cheapest way possible, my vote goes to the 225 with a hairdryer on it.
Just my 2-cents, and probably over-priced, at that...
Good luck in whatever you do; I'm sure it will be neat!:happy1: