Does an increase in airflow (intake or exhaust runner) move peak torque up or down the RPM band?

Oldiron440 said

It's funny that the Boss 302 heads were brought up because I happen to own a pair. I was looking for a pair of 69 - 70 351W heads and a guy said he had a pair for a $100 but they tuned out to be Boss heads with new SS valves. Any how the runners and valves are huge, I could see them going on a 400 M motor easly.

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They have to have some kind of mod on the intake side to be used on the Cleveland blocks if they are true BOSS 302 heads. Although they are almost identical to the Cleveland 4V heads, there is a difference. I have a complete 1970 M code Cleveland. 4V closed chamber heads and all. They are pretty formidable engines when built right. I agree about your 400 statement. I've always said the 4V heads would have been just right on the 400. Those intake ports are just too huge for the 351......but they can be made to work if you're careful.