you can fool the computer in to still making over drive work in it but you,ll get constant check engine light all the time on it another thing that will affect it is the fact that you wont have the tps to help govern things on it like the shift and the fuel supply,but even that to can be made to work right,the real problem will be the fuel supply,your going to have to reduce the amount of fuel pressure and that wont work out to good on it,i did one once but i did away with the computer all together and wired over drive strait in to work on a by pass switch,but in doing this you,ll also be affecting the torque converter lock up switch in the transmission,all these things work together on those trucks,you,ll still have the computer and it will still function certain things ,they will just malfunction more often,the tps sensor will be your biggest concern on doing this one,it will affect the transmission on it,if you was going back to basic electronic ignition with a simple system you could hard wire the torque converter switch and the over drive switch to come at any time you chose for it too,but you wont have that option doing it the way your wanting to do it,your a lot better off staying with the set up you have now on it,unless you want to go back to the bare basics on it this system you have now is the best to deal with,good luck.
