Have you actually torn one down? Run flow numbers on the cylinder head? Checked out the block design?

The QR is better in so many ways.. The SR will make more power in stock form, but the overall potential isn't there like it is for the QR. Here's why..

QR head flows about 90cfm more than a SR head on the intake side, and about 40cfm more on the exhaust side, at .450 lift.

QR head is cam on bucket.. One of the big reasons that the SR can't rev, is that it breaks rockers, or slings them off. That design flaw will never allow you to safely rev the SR to anything meaningful. The QR can rev as high as you want.. nothing to break.

QR head bolt is much larger than the SR. More clamping force, means less chance to lift the head. Also, the SR's threads sit in a sand cast block... which means when the boost is cranked.. you can actually pull the threads out of the block.

QR has a die cast block, SR is sand cast.

QR has a bed-plate design.. SR has main caps and a girdle. Bed plate means the crank is secured in the middle of the block.. The SR's design gives more chance for flex/shifting of the main bearing structure.

QR has 3 times the oil pump flow as the SR. This means WAY better oiling, and less chance to spin bearings.. which SR's are famous for.


Those are a few reasons... What's it all boil down to? The QR makes way more power, with a much better powerband than ANY SR could dream of.. at lower boost levels. When sleeved, the QR block is good for 4 digit power levels. You will never see a SR do that. That's why you don't see SR's running with the big boys in the drags..

Travis