I have the Downey headers on my truck and like in the other posts no seat of the pants changes, I am carbed though and since I have other mods the headers my have been less noticable. I am also running stock from the header back so I may have some issues there on reducing performance. No leaks either and they are 50 state legal. I do have Thorley's on my MH and you can definatly feel the difference, though it has a 454 in it.
