I just finished building a 320 GMC, and I have dealt with most of the advertisers in the 12Port News. I've had some good luck with Stovebolt, but with the dampner after several discussions with Mike Kirby of Sissell's Automotive in CA I decided to buy mine from him. It is a aluminum Fisher that has the pulleys built into the dampner. If your running a performance engine, you will want a fluid dampner or the one like I have has clutch's, friction plates and springs in it to absorb the heat and torsional shake. Mike says that he has had the best luck with those. So that is what I went with, but this engine only has about 20 hour or less on it. I'm getting it ready for dyno service very soon. I hope this helps you some. Good Luck!