holley 670
In my opinion, for your application, the 670 is not too small when tuned correctly. Your shift point is probably in 5500/5700 range i would think, and that should feed it pretty well considering in the 1/8th mile you'll spend little time at peak rpm.
With the improvement in 60' times, and the loss of 3mph, which is considerable, you're losing mid/upper range performance. One of the reasons why I suggested a little earlier secondary. Without going crazy, it's actually a lot harder to get a vac. sec'd Holley into bog range vs a "air door" style carb.
I should have mentioned this earlier.....Your truck is super nice. :thumleft:
Good Luck