BDS- Blower Drive Service can and will answer your questions on building a blower motor. Parts including pistons for your application are available through them as well ,,and the knowledge base there is fat. Look them up on the web its should be a toll free number
Rotating assemblies need to be balanced in a shop on a balancing machine to get it right Period!!
forget the woodshop tools and spend a few dimes to talk live to a pro and browse your internet on engine balancing for longivity plus performance gains.
A good balance job will free up many horses and also NOT cost over a couple hundred dollars. Balancing includes wristpins, spiro-locks, piston- rings, bearings plus the crank with flywheel and harmonic balancer attached and balancing both the big and little ends of the rods, ya can't do that with the old high school wood shop tools. There are special tools and holders for engine rotating assy work, I can provide you with a top builder and engine balancer shop owner to speak to if ya want to talk a bit. It isn't that exspensive to do it right the first time.
Have your ignition system set up correctly either by using the correct electronic pieces from MSD or send the distributor to BDS for curve work and talk to them for timing needs. Your timing and curve work in the ignition will make or break you for keeping the engine cool and living at most any PSI-boost you will run on the street.
Exhaust side of your heads is the power side with a blower, again talk to a blower shop and learn all you can,Eagle rods are very good for your application and use only FORGED pistons, hyperkinetics will not live long and plain old cast types won't go more than a few stop lights.
Good luck