I ran a 750 Mighty Demon on my 340 with 13:1, ported heads, big flat tappet........

On more than one occasion, it back-to-back, outran a custom 950 (for my car) and another 950 HP.

I hope yours picks up with the 950.

BTW, my 950 flows 964 CFM and the Mighty Demon 750 flows 950.7 CFM.