Fishman1. these guys are telling you Straight up and they are right. You may go quicker with a 750. Story- 1 month ago I went through tis same thing it's posted on here. I have a 434 -666 H/P 15 to 1 comp. it had a 950 and ran 6.20 in the 1/8 and I thought it would run faster with a good Dom. well NOT I bought the HP Dom. and a brodix intake and no matter what I did I could not get it to run any faster with it matter of fact it slowed it down to 6.33 and that was it. $1400.00 down the tolit. I put a dart intake and a new 950 HP back on it and droped my octane down from 114 to 112 and now it's running 6.10 consistently in the 1/8 . TO MUCH CARB IS BAD it cost me a lot of money to learn that lesson.
Be safe and have fun. Andy