im putting the modified motor and as its almost done, i've come to the conclusion about the VATS system(vehicle anti theft system), when i take out the 92' 3.1 automatic tranny, and install the 88' 305 TPI and 85' T-5 tranny, what am i gonna have to change on electrical wise, can i use the same key, i have the ECM for the 88' 305 TPI, can the motor wiring harness be used on the gauges for the stock 3.1 motor, basically what im asking, whats gotta be changed in order to put an 88' 305 TPI in from an existing 92' 3.1 w/ auto tranny besides the fuel pump,torque arm,crossmember,clutch,flywheel,engine mounts. Most importantly do i have to rerout the fuel lines??? whats the most difficult change that i have to do, name every possibility if u could, thanks

 

im sure one person has done this modification

 

ask that question here:
http://sethirdgen.org/

James

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1985 Z-28, 350 TPI, T-Tops, edelbrock 6085 heads, ZZ4 cam, accel base/runners & 24 lb/hr inj., ported plenum, everything gasket matched, crane AFPR, SLP 1 5/8 headers, single 3" flowmaster catback, 3" Catco cat, modified tranny, 165 ECM & ARAP code, MSD 6AL/wires, edelbrock STB, Spohn SFC/LCA/PR, GW "wonderbar"

 

wow thanks for all your help guys, i can see why everyone says that this board is useless

 

Moderator could u please close this thread, it seems to me that this thread in this board is useless, and if no ones gonna help me out id rather close it thanks

 

Okay; if you are using the '91 ECM, then you have to use the correct VATS key. If you are going with the older ECM you'll have to switch VATS modules (if the older ECM uses VATS), or you won't need to worry about the VATS at all (if the old ECM doesn't have VATS).

The swap should be pretty straight forward. I believe the fuel line run on the driver's side in both cases, so they won't have to be changed. However, you may need to find the correct flexible lines that run from the hard line to the engine itself. You'll have to check elsewhere, but I believe that the fuel pumps in the MPFI and TPI were the same.

The harness will run all the gauges, but I think you might need a new tach--I know the V6 and V8 are different, but I can't remember if the difference is only cosmetic (i.e. in the position of redline).

If the TPI you have is 88, then I hope you got the serpentine setup. You'll have to swap that over as well. You'll have to have the A/C system evacuated as you'll need to put a V8/serp setup hose on that allows the condenser to be mounted on the driver's side (the V8 config) as opposed to the passenger side (the V6 config).

That should be about it...sorry I can't help w/ everything...

 

OK, you cannot use the 91 computer because it's for the v6.

With the '88 computer VATS will be disabled, but there will still be a starter disable relay tied into the VATS module. If you arn't using the right keys, all you need to do is by-pass the relay. Keys or VATS pellets won't make any difference after that.

Or: (Just a thought)

Get a '89 PROM and keep VATS active.

 

Also... you will need to move the brake line that runs across the front crossmember as it's in the way of the v8 mounts. You need the v8 tach but the dash wiring should be similar. As for the airbag I have no idea. Change the computer and engine harness, a complete harness helps so you can keep what you want and cut out the wires that you don't. All the relays and brackets from the v8 help. Radiator... all that good stuff you mentioned... has to be changed.

Good luck with your swap, maybe some day prolly after winter now... I'll start mine.

 

Wait could i leave my stock MPH gauge, im using a 87 305 TPI w/ 87 COmputer and harness.