I have had my 87 for 20 years and have restored the body twice, the truck is in great shape but the motor just gave up. I found a 99 with a 4.0 ohv 5 spd with low miles for $300 that runs great but the body is shot. I was wondering if anybody on here any ideas how hard it would be to swap the 99 4.0 into the obd1 truck. i know its no big deal to bolt it in but my concern is with the wiring and pass keys. I would rather not switch the dash. Any help would be appreciated. Thank You

 

Welcome to the forum


Shouldn't have too much of a problem, '99 still used analog dash, so temp and oil gauges will be fine, fuel and voltage doesn't change.
If you have an AMP gauge then you will need to locate the SHUNT in the engine bay so it can be used with 4.0l alternator.
Problem will be with speedometer, 1998 and up 2WD transmissions no longer had speedo cable hook up, you may have to do some trading to get a 1997 or earlier 4.0l trans, assuming manual trans
If 5-speed automatic then you may need to use one of these: ECD-100
And swap in the 4.0l trucks rear axle to get the Speed sensor(VSS) to run it

And OBD2 in '99 was all about the engine so most of the wiring is there.

PATS key and PATS reader can be placed together under the dash, so each time you start engine(start computer) with current key, the computer will read correct PATS key and allow you to start the engine.
You don't get the benefit of PATS(passive anti-theft system) this way but your 1987 never had it to begin with

PATS reader is a "wand" around the key slot, called a transceiver, it and its wiring can be pulled out of the '99 vehicle and put out of the way in the 1987

 

Thanks for the reply Ron, It would be nice if its that simple. Looking at both truucks tonight it looks like it might be bettter to go with 93 mounts and I forgot about the cable speedo thanks again.