I will be installing a TKO in place of the TH400. The big block has a giant Lunati Thumper cam (7" at idle) that just gagged when punching it from idle with am 850 double pump. That combo did OK at 2000rpm up. To help off the bottom, I replaced the 4150 with an Avenger 670cfm.

Anyway, doesn't the carb rule change when I go to a manual? Won't I need a double pump again?

I hate playing with jets, pump cams, and springs on this car, how in the crap do you find the right main jets when you can only be full throttle for a couple of seconds? There is no dyno close.

Are there any shops out there where I could give my motor cam profile, compression, ignition system timing, altitude, and etc, and they could set up a carb reasonably close for me to just bolt on???

you might need to do some minor adjustments, as it no longer needs to idle in gear, but other than that, it will run fine.

So the vacuum 670 will work? What would we all say would be the right cfm ball park for that motor, a 468, 9.5:1, big cam, MSD set at 18-38, Hooker comps... The stumble off idle drives me nuts.

750/770 min for good performance. Your too small for anything other than casual driving.

Your carb can be fixed by adding more timing :D

I was so sick of the super-bog with the 850 that I went the other direction to keep some venturi velocity going easier. Too small, huh?

I run an 870 DP from AED, no bog.