Wow, I never thought it would be so hard to find out which 1227747 PROM code will work with a 350 and TH400 tranny. I now know that AMUR does not work. When I hit about 25-30 the tranny "shifts" out of gear so to speak. It's not driveable at all. I disconnected the kick down shift wire from the tranny so I could at least drive it and the motor sure runs good. Does anyone know where I can find out what codes are for a 350 and a TH400? ANLW, ARJT, AKAJ, AMUN, etc, etc, etc. If it makes any difference I have a shift kit in it and 3.73 gears.

Try AFBZ or AFCB. These are '7747 cals for a L05 and M40 trans. Federal emissions.

RBob.

Thanks RBob. I've been learning about all this and today I got some specs on the 350 I just had built and installed. Here is what I am told about new the motor.

Flat top pistons, 9:1 compression. The heads are standard 350 heads, not the TBI swirl heads. Cam specs are... Lift: .420 Intake, .443 exhaust. Advertised Duration: 270 intake, 280 exhaust. Intake manifold is the stock one off the 305. Exhaust is also stock at this point. No california emissions. Injectors are new 350 injectors. It has a new 350 knock sensor and ESC module. They claim it should be a 300hp motor even with stock intake and exhaust. Does that sound reasonable?

Would either one of those chips be ok with what I have or do I need to bite the bullet and have a custom chip made?