12 Second N/A Slant 6?

273 said
PowerWagon896 with your spec i got 291hp@6000 287ft-lb@4500

Looks like a 3200 RPM stal convertor would work pretty well.

Fairly nice TQ @ 3000 (250 ft #s?) & the TQ band builds fat from there & holds well in the upper RPMs..

Running 26" rubber on a 4.56 & shifting @ 6500 RPM...

1st to second shift @ 6500/45 MPH brings RPM down to 3900 to pull 2nd gear

2nd to 3rd shift @ 6500/76 MPH brings RPM down to 4500 RPM to pull out 3rd gear.

6300 RPM is 107 MPH. If the car can pull out 3rd to 6300 RPM, thats a solid high 12s pass.

Here's a handy gear ratio/MPH calculator that I have been using for several years.

http://www.f-body.org/gears/