700r4 On Older 350 ?

[440sixpack]

Hi, kind of a newbie to GM products so I hope my questions aren't too lame.

I'm looking at a nice K10 that has had a 700r4 and a newer part time transfer case installed as well as a newer fuel injected engine. I can live with the overdrive transmission but I want a 4v old school engine under the hood and he still has it.

can I bolt the '77 small block in place of the 90's fuel injected 350 or is that a problem ?

 

[1987 GMC Jimmy]

Is it TBI, MPFI, an “LS” motor? What’s the year of the truck? The short answer is the transmission’s not gonna care (much), but as far as what you have to do elsewhere it depends if it’s something that came with the truck originally or if someone swapped a bunch of stuff in later.

 

[440sixpack]

It's out of a '95 I believe. it's a running driving completed conversion . I can live with everything except the engine, so if I can bolt up the correct engine I'll be happy.

 

[1987 GMC Jimmy]

I’d get a few more details. ‘95 came with a 4L60E which needs the PCM. If it does have a 700R4, the proper way to have made that setup work is to have flashed transmission control parameters out of the computer’s MEMCAL or use an older computer and harness that would only control the transmission’s 4th gear torque converter lockup.

‘95 is also TBI which, assuming it’s got a 700R4, is pretty easy to convert back. You can do it with an adapter or a different intake and not have to put a whole new engine in. Just take out the sensors and what you don’t need wiring wise, and you’re done. You just need a way to control lockup on the 700R4. They have toggle switches for swappers, and the factory trucks used a vacuum circuit (79-86) and later the ECM (87-92) to do it.

If it were me, I wouldn’t worry about the TBI unless you’re a die hard originality stickler. In my opinion, it’s simpler than a carb (fewer moving parts) and easier to perform rudimentary diagnostics on using a multimeter, paperclip, and fuel pressure tester when it breaks instead of just guessing or having to leave no stone unturned in many instances. The only way carburetion wins in my book is its easier to soup up for performance than Rochester TBI, it requires little to no electronic input, and the mechanical fuel pump is (usually) easier to change. Otherwise, it’s not that different, and if you’re close to the mountains, the TBI’ll compensate for differences in atmospheric pressure where, unless you’re running an electronic carburetor, that won’t happen. It’s pretty much the same thing as Chrysler TBI, which is 88-94, I think? Something like that.

 

[Rusty Nail]

We'll send a bill, what's your address?

 

[Joe T]

That would be the same as an 87 V10 then. TBI 350 with a 700r4. One year only kinda sought after. Only had SUVs and HD trucks after 87 in the square body, till 91. So maybe this was where he got the parts.

They used that motor to 1995 then went with the L31 Vortec 350 in 1996 which is a much better power maker and design.

They changed from the 700r4 to the 4l60e in 1994.

As long as it isn't a fire hazard I would leave it or find another truck.

As to your primary question, I assume you didn't buy the truck but if you did I think any small or big block will work on a 700r4. Pretty much any engine GM made that you’d think of for that truck will bolt up.