W2 heads are great heads and like you said they are plentiful. With the Bloomer heads we are making a honest 680 hp with only 11.2 to 1 compression. They say that a full point of compression is worth 15-20 hp. So with a full 14.5 to 1 compression 725 hp is possible and porting the intake might be worth another 5 hp or so. I think with a maxxed out Bloomer headed engine that you could make between 730 and 750 hp. And that's inline with the best W2 engine I've ever seen. That's about the same hp that the SBM prostock W2 engines were making back in the day. Intake , rocker arm and header selection is better on the Bloomer heads as well. I'm tickled to death with the performance of my Bloomer heads. And the car is almost 2 tenths quicker than I ever thought it'd be.