I used the entire driveline from a 1989 Chevy S-10 Blazer - 4.3L V-6, 700R4 automatic transmission, and NP231C transfer case. The motor mount used was the Advanced Adapters bolt in saddle mount for a 5.7L in a YJ chassis. 

Well, as of Friday May 27 2005 the YJ is up and running on the 4.3L engine. All seems to be working well at this point. I had to modify the 'Y' pipe from the V-6 to clear the front driveshaft - I had a custom pipe bent. I have posted my wiring diagrams from splicing the 1989 Chevy S-10 engine harness to my 1992 Jeep YJ chassis harness. I removed the entire engine portion of the Jeep harness (i.e. injectors and sensors). I did not use the mechanical fan on 4.3L and opted for a 2000 cfm electric fan sitting in front of the S-10's radiator. (yes, I used the S-10 radiator - it was way cheaper than a custom conversion radiator)

The wiring diagrams are posted for information only I cannot warranty their accuracy, every installation will vary. USE AT YOUR OWN RISK! (standard legal disclaimer - don't be stupid and blame it on me!)

A few key points ...

The Chevy fuel pump MUST be used - the Jeep TPI system pumps at 19-39 psi and the Chevy TBI system operates at 9-13 psi. The engine will not start with the fuel pressure too high. 

Custom driver's side of Y

"Finished" engine bay

Wiring Diagram

Links to .jpg file

YJ with part of blown 2.5L

AA saddle mount

4.3L/700R4/NP231C

ECM sub feed and ALDL

Broken alternator bracket

Shifter placement

Chevy and Jeep fuel pumps

2WD trial runs

Left side S-10 crossmember on YJ

Current Photos

Piece of factory pipe left

2000 cfm Fan

Project Photos

'89 S-10 Blazer - Donor

Set everything together

ECM & DRAC in glovebox

Broken alternator bracket

Sub feed fuse panel

Chevy Y pipe to an XJ cat

Chevy on Jeep assembly

Right side crossmember

Together & Clean - bling, bling!

Shorty Cat and Turbo Muffler

Optima power with disconnect

Wiring Diagram

Links to .doc file

YJ gutted

Bob's hoist

Cut everything to clear the way!

S-10 bulkhead connector

Jump start

B&M shifter cable routing

cat to YJ Pacesetter muffler

Close up

Hack job on the Y pipe