I've got their new system on my 64 Belvedere's 383. Quality is great & Don curved it for my stock 330 hp 383. Only problem seems to be that FBO's dizzy has to run off manifold vacuum & not port vacuum, so my 383 still detonates at WOT. I've called Don 3 or 4 times & he's been helpful, but said my carb is probably too lean. Carb isn't lean at all, so gotta figure it out. Really like the quality, but wish I'd gone with an Accel dizzy & MSD box.