Originally Posted by joshuabrodie
I have 95 gmc tbi 350 the crank broke. So i bought a 96 chevy tht was wrecked but complete truck runs. I need info. on swapping the wiring harnesses and compters? do i need to keep the computer in the 95?
This is quite a job, the 96 Vortec shares little in common with the 95 TBI besides exterior sheetmetal. All the systems are different from the fuel pump, exhaust 02 sensing in particular, the wire harnesses, sensors engine and transmission are different, and we're not even to the engine where the larger differences reside. It's not that it can't be done, but it is a really big effort that pretty much will touch everything except the exterior paint and interior upholstery. As has been pointed out this change bridges the divide between OBD1 emissions systems and OBDII. This is like the difference between night and day; it is major. In terms of 6 of 1 or a half dozen of the other I'm not sure that putting the 96's systems into the 95 is any less effort than putting the 95's sheet metal onto the 96 frame, assuming the frame is undamaged.
The easiest way out is to use the GMPP TBI to Vortec intake pat number 12496821. These are pricey but as you'll find out well worth their weight in problem reduction. This will let you use the Vortec motor right up to the heads with your 1995's TBI injection and systems. It does require externally plumbing the EGR which should be simpler because the 96's exhaust manifold already is provisioned for this. So all you need is some tubing and fittings to connect the locations together. http://www.jegs.com/i/GM-Performance...oductId=750534
You will also need to reuse your TBI distributor and all the sensors.
The Vortec uses a different front timing cover and damper. This is to provide a place for the crank position sensor which TBI doesn't use. Your choice, you can replace this stuff with the 95's or reuse it with the position sensor not connected as you have nothing to connect it to. But you may have to build a timing pointer. Also, the plastic Vortec timing cover has the crank seal as a molded in part or not there are about 3 combinations of seals and covers, in my opinion using the 95 cover and seal simplifies things. The Vortecs use some better timed cams than the TBI, the computer might need to be rechipped to support this, you'll find out when you get there. If runs fine no problem, if it's a bit herky/jerky either an adjustable fuel pressure regulator or a new chip is in order to realine the fuel delivery with air flow.
Looked like a simple swap on the surface didn't it! This is typical of everything across the OBDI and OBDII divide which is roughly 95 to 96. But different brands or models start the swap in full or in part actually back as far as 92 and certainly by 2000 everything goes out the window on commonality between years, models, and makes.