how much weight can you take off a 170 crank and be safe. Going to build a short stroke motor. Alan

What year crank?
Like the 225, the first 2 years of 170 production used a "big counter weight" (heavy) forged crank.

That aside... 2 to 3 lbs of weight reduction is possible if you work at it.
In general, the closer the weight is to the crank's centerline, the less impact it has on performance. Seeing that a 3 1/8 stroke 170 crank does not have a lot of "far flung" weight, your efforts would be better served by getting weight off the con rods and pistons.
DD

Pistons are no problem, is there a alum rod for the 170?

Aluminum 5.7 c to c SBC rods can be made to work if you do a little custom crank pin grinding.
DD

Thanks Doc,
Will be calling on you somemore for this build. Alan

Darn Doc, I thought that would be my ace in the hole. That's what I plan on doing is the 170 (would like to rev with boost) and 350 stroker rods with pistons that are like a hockey puck.