Get that done? Just buy that A14 - it cost less than paying someone to do the same to your A14, and its already done. But it won't go faster than an A12. My stock A12 had no problem doing 75 MPH on the LA freeways. Sure it ran 4500-5000 rpm, but t hat doesn't hurt an A12 (redline is 6000 rpm). If you put the A14 in your 1200 it will still need to rev to the same RPM. You can fit an overdrive transmission to lower the rpms, but getting to higher speeds still means accelerating in 4th gear. Then once you get up to speed, shift into 5th for quieter cruising.