I've research American Speed engines and talked with their builders. They use all the quality goodies and know the correct details of assembly. I've purchased a mild 350 CID from Procell engines, (TX). They build 383's...nice pieces. The people at Procell were great to deal with. Whatever you do insist on a dyno sheet and review it with the tech in person or at least by phone. I think the GM crate 383 idea is a good one...great parts, good warranty.