you may remember i posted 2 weeks ago about the boys taking a old 302 -auto motor and transplanting into a new F150 that had a 4.2 V6- manual. V6 flywheel was too small so they bought a balanced flywheel for a 302 and installed. Long story is i removed the motor, pulled the flywheel, balanced it for the 28 ounce off set design, and it now runs great.
For thost that are interested, with the balanced flywheel the truck would start and run very rough, vibration. It would not rev up and had no power off the line and about 45 MPH top speed. I originally thought timing, cam, compression, carb, etc. After checking everything we pulled and looked at the flywheel. Now for some data. The original flexplate had a weight on one side about 4 inches long 1 inch wide and 1/2 inch thick. I calculated this to be in the 8-10 ounce weight ranged. AFter talking to others on this site, i chekced the off balance on the harmonic balancer and it appears to be in the 18-20 ounce range. Adding this together i assume i had a 28 ounce "off set" of weight. The new balanced wheel would be about 1/2 pound off compared to the old flex plate. What i did was bolt the flywheel and flex plate together so i knew they were in alignment, then marked the location of the weight of the flexplate, onto the flywheel. i copied the weight 180 degrees out, then used the millilng machine to cut out 1/2 pound of weight. 1/2 pound light on one side should be same as 1/2 extra weight on the other side.-- Checked the balance on a straight edge like you do a lawnmower blade. In the end, everything worked out great. motor runs excellent and much more HP than the original V6. Thanks to all on the site for help.

 

Ok, glad it worked out for you, Steve. A little unorthodox an approach perhaps, but if it works, it's all good.
Nice to have a milling machine for that. When I was racing, we had to run a stock flywheel but it could be lightened. When you turn the back of the flywheel, you remove the cast in imbalance weight, so the machine shop rebalanced it on their balancer, drilling holes in the back on the opposite side from where the original weight was. Not something I'd be brave enough to try without a crank balancing machine, but hey, more power to ya!