Join Date: Jan 2019
Location: Sedgwick, Kansas
Both heads are excellent. It's my belief that the chamber design is a little better on the AFR's compared to the TW's. While they are very comparable on the top end, with the TW's possibly even delivering a few more peak horsepower due to the canted valve design, I think the AFR average power would be a little better. The AFR's BSFC is better, too, which means better mileage.
So - for street use, I'd buy the AFR's. If you're more interested in racing, the TW design has slightly more potential for peak power - but not much.
"No matter what you are, be the best one you can." -Abraham Lincoln