Thanks for the info. Reason for the .550, instead of .590 didn't think heads would take the .590. Can't do head work right now, but wanted to work towards it. Have built diesel (Caterpillars), pontiacs, and chevys, so the wrenching isn't a problem. Porting and polishing, not so much.
I really like the way the true duals sound, but would like some better low end than what I have now. Willing to give up some to keep the true duals.
Was looking at dyno charts for the TW-6hg and it looked like it was producing good flat torque from about 2500 rpm.
Open to suggestions, but looking for gear drive cams.
P.S. reread and saw that heads will work at .590 lift???
Didn't think the '03 heads would take that much lift.