For a Streeter that spends most of it's life at under 3500 rpm, I will take Compression over flow. 3500rpm is about 38 mph with 2.94s in a 904-first gear. Even with 3.91s, 3500 gets you about 30mph.Your heads could flow 700 and it wouldn't be worth a hoot. But 3 points of compression will pay back big time,all the time, every time.