M1028 th400 shifting problem w/502bbc swap in

[hokie8358]

Just swapped in a 475hp, 502bbc stroker motor in my 86 cucv m1028! Needed more hp to turn 39.5 swampers!
I knew i should swap out the diesel torque convertor since it locks up quicker in low rpm range!the 502cid idles around 1000-1300 rpm's. So i swapped in a hughes stall convertor 1500-1900 and i ve got the vaccum line hooked up to the holley 850 double pump. When i take off,the truck goes maybe 12ft and goes to 2nd gear, then maybe 20 more feet and dumps to 3rd! Sometimes when it needs to down shift to 2nd from 3rd,i have to manually do it on the column or either stomp the gas pedal to make it kick down!
Someone told me maybe you have to switch out the diesel governor for the gas gov. So i took out the gas governor from a th400 and put it in! Yes they have diff. Part numbers,but made no difference at all to the shift patterns! The stock torque convertor on 454 bbc i heard is around 900 to 1100! I am wondering should i go back in and swap out torque convert. For stock one? Please give me some insight! Baffled on this one and fed up shifting manually!!!

 

[woodywood]

too muck vacuum pull the hose off the modulater valve the should be a little flat head screw turn it in and drive should fix it.i would only turn it a turn or two clockwise then drive again till you like it

 

[patracy]

502 still has the same 4" stroke of a 454. So it's not a stroker motor.

Did you replace the modulator as well to one that is adjustable?

 

[hokie8358]

I am sorry! My bad! Big block was a 454 that was bored and stroked to a 502cid. Was built by terry walters engine service in salem,va! Or as i was told anyway! Lol! None the less,yes i did swap out old modulator with one from auto zone! Not sure if its adjustable!

 

[hokie8358]

Is the flat head screw inside were hose goes on modulator valve?and do you go clockwise or counter?

 

[patracy]

I am sorry! My bad! Big block was a 454 that was bored and stroked to a 502cid. Was built by terry walters engine service in salem,va! Or as i was told anyway! Lol! None the less,yes i did swap out old modulator with one from auto zone! Not sure if its adjustable!

Stroked would mean that the crank throws have changed. So it's only a bored engine.

Is the flat head screw inside were hose goes on modulator valve?and do you go clockwise or counter?

Yes inside the hose port. Clockwise to raise shift points and firmness, counterclockwise to lower.