Sayanara low speed TQ production....and part throttle will obviously be soft (penalties of a sheet metal design assuming short direct runners).

Seriously, for a heavy GTO there might be nothing better than the FAST. Those long runners will really help out. A sheetmetal might give up 40 ft/lbs or more from 4K down to make 20 more HP upstairs....OK for a race car or a serious Friday night bullet but it might not be the hot ticket in a dual purpose heavy street car (assuming your's is).

Take this as general advice seeing I really dont know your particular goals, but just something to consider for others reading blindly thinking a sheetmetal is the answer to everything.

And the whole "ET heads outflow a FAST" thing is sooo funny. Most decent ported heads certainly will....the AFR cylinder heads being no different, but the right combinations are still putting down very respectable numbers. Hell, my little 383 is mid 530's thru a ported FAST at 11 to 1 CR and a very streetable cam. The ET heads are nicely done and the larger runner (cathedral) versions flow a little more peak #'s than our 225's, but we are talking about small percentage increases here. The right ET combo with a FAST would still be a very lethal piece IMO and make alot more bottom and midrange grunt than the same set-up with a sheetmetal. Even though the FAST is a restriction at the higher valve lifts, a good head will still utilize and draw thru it very effectively. It wont make less power than a lower flowing head because the lower flowing head is less choked....the better headed combo simply wouldn't be as optimized, thats all. Another Internet rumor that started somewhere on these pages undoubtedly due to soft dyno numbers I would imagine. And so they could sleep better at night they shared that theory with two friends....and they told two friends....and so on....and so on.....you get the picture.

Tony M.

 

Hmmmm