Help with 340 compression + cam change

More lift ought to work with the idea that the cam is limiting the flow more than the heads, 'specially if it gets the valves open more quickly.

Probably stating the obvious, your 1/4 mile time seem a bit long for what you have.....and the top speed looks to be around 5k RPM for your gears. Might be that things are being choked down.

And there may be other things going on. Others can comment better than me on that....