I have a quick question you might have seen my other posts but my car has ran a best of 12.10 at 113 with 2.73 gears with a th400 trans 26" tires. i only use 2 gears through the 1/4 mile i shift into second at 6700rpm and and cross the line at 6800 rpm in second. i had just put a set of 4.10's in it put a 3 gallon cell up front and got some control arm relocation brackets. my question is since i went with the 4.10's i heard my trap rpm will only be like 6100rpm in 3rd will this cause me to run slower time or will it be about the same. Im hoping to hit around 11.70 . also taking front bumper support off and of course the stock gas tank think i will be able to do it.

 

Should be quicker over all with the 4:10 if you can get traction with the 26" tires because your 60 foot will be quicker than it was with the 2:73.
Might want to borrow a friends 750dp to see if that might help too. That 650 might be just about outta breath at 6800.
Those heads would like to see a bit more lift, too. Get it as close to .600 as you can with the 215 Darts and it will pull like a train. 1.6 rockers could help to get around .540 lift with that cam. You should have plenty of clearance with those pistons.