Honestly i wouldnt have raised them,for a couple reasons.

the port actually works very well for its size to begin with and can go over 200cfm at stock size.and the cross section stays fairly close up to the header flange.

also idf this is going in a early model ford the headers usually leave a whole lot to be desired and probably pinch back down after the flange,which isnt what you want so soon after the valve.

but after sayin gall that i would be suprised if it actually hurt you,may not help at all though.....

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1964 Falcon hardtop,terrible running 302 and t-5.should be a good project car....