Don't forget the over the counter angle plug 492's.Back in the late 80's or early 90's, either Car Craft or Hot Rod did a flow bench comparo of several of the cast iron "smog" heads common in the late 60's through the 80's. The 441 flowed the best of all of those tested. In fact, at that time, the only factory heads that out-flowed them were the double-hump heads (461, 186, 462, etc.), and the 291 turbo heads. FWIW, the 487X came in second, and the 882 came in nearly dead last.