Intake volume is 170cc, and chamber is 64cc.
What machine work do you need done to them? Hard to say if it's worth it without knowing how much you're gonna pay for the work. New heads can be had for $440. Don't forget the self aligning rockers.
With porting, which they don't need much, they can flow quite a bit. Already, they can support around 400ci for a torque motor, and they'll make excellent power to 6500RPM on a 350. If you go all-out on porting these heads, they're junk. You need to do minimal work on the ports to keep the swirl effects intact.
Are they worth it, oh yeah! Especially for the price you got them for. You should be around 400HP with that cam and compression.
Lead Mechanical Engineer
Art Morrison Ent. Inc.