dyno numbers from my 340 just for reference

You might have a bit too much timing, 340 seem to like 34--36, did you tried backing the timing off a tad?

I believe the 300 hp in back, its torque the little 340 lacks a bit but a 3,000 stall and 3.91--4.10 gears solve that problem.

The 750 eddy is costing a bit of power--but sure its smoother and more reliable for a longer time then a 750 dp.

Would I change anything, no--unless you went dual carbs. Well may be a tight 10 inch converter, it knock the et down..what gears it got in back,, 3.55 or more should be fine..btw, where in MI are you, I'm out by Novi, got a dual carb 340 with hp exhaust, am very happy with it, never dyno, just enjoy