THEFERMANATOR
07-04-2019, 11:27 PM
I've been reading and reading and reading some more on this. My neighbor has an 88 R30(square body, 2X4, dually, 4 door) with a 5.7L TBI and a turbo 400. His trans crapped out on him, but he really likes the truck, so he wants to put an OD in it since he has no plans of selling it, and the lack of OD was his only complaint with the truck(plus the shops around here want over a grand to rebuild his 400). It recently had a brand new GM crate motor dropped in it(the 2 bolt main 1500 version since GM discontinued the 4 bolt main version) due to a shop screwing his engine up, so an engine swap doesn't make much sense. So I figured we would do a 7427 swap since an aftermarket trans controller is almost $600 by the time you pay shipping and taxes. I lucked out and found a 7427 with a BNKM chip in it and a VSSB from the same truck with plugs, so I'm hoping I won't have much trouble with it.
The only mods to the engine is the heated air intake duct at the air filter housing to the exhaust manifold is gone(we live in Florida, so cold temps isn't a concern), 4" duct routed up in front of the radiator, a set of cheap stainless headers(long tube 1 5/8" IIRC), and a 3 wire heated O2 because he was tired of it reeking of fuel at idle.
If I'm reading everything correctly, his 88 uses all the same fuel, emissions, and ignition as the 95. So all I should have to do is re-pin the 7747 to the 7427, add in the 11 wires to the trans plug, 4 wires for the speed sensors, bypass the EST, change knock sensor, and add in a relay to give the N/C brake input for the 7427(I know 700r4 had this wire, but didn't know if th400 trucks did). Does this sound about right, or am I missing some?
I already know about the speedo as I have a 90 SUBURBAN cluster coming for it. Just trying to help out my neighbor as he's a good neighbor who helps me out all the time, so just trying to return the favor.
The only mods to the engine is the heated air intake duct at the air filter housing to the exhaust manifold is gone(we live in Florida, so cold temps isn't a concern), 4" duct routed up in front of the radiator, a set of cheap stainless headers(long tube 1 5/8" IIRC), and a 3 wire heated O2 because he was tired of it reeking of fuel at idle.
If I'm reading everything correctly, his 88 uses all the same fuel, emissions, and ignition as the 95. So all I should have to do is re-pin the 7747 to the 7427, add in the 11 wires to the trans plug, 4 wires for the speed sensors, bypass the EST, change knock sensor, and add in a relay to give the N/C brake input for the 7427(I know 700r4 had this wire, but didn't know if th400 trucks did). Does this sound about right, or am I missing some?
I already know about the speedo as I have a 90 SUBURBAN cluster coming for it. Just trying to help out my neighbor as he's a good neighbor who helps me out all the time, so just trying to return the favor.