1st gen engine interchange

Hi All. I am new to the board and looking at picking up a 1st gen with a blown motor. It is a 95. I looked around at the usual sources for a replacement but a lot of sites are saying the replacement is 95-97 and 98-up are different. Can anyone help with what the differences are, minor or major? If it is simply different connectors I will swap over sensors but if the castings are different for motor mounts that would definitely be a show stopper for a 2000 motor. I am pretty much a jeep guy and have built several from the ground up but am looking for a parts runner and this truck seems perfect for that. Any help is appreciated.

 

I know the ignition systems changed a couple of times during the first gen on the 3rz. Which would probably equate to a ECU and harness change. Not too sure about the 2rz, maybe someone will chime in that knows those engines better. As for actual engine dimensions I seriously doubt that there is any difference between any of the four cylinders in the first gen at all. As in all the 3rz's probably used the same block and motor mounts through the years. The 2rz used a slightly different block with no balance shafts but the motor mounts are probably the same.

 

I just did a swap on a 96. They used an 8 port intake on the first couple years, 4 port after. The 8 ports are harder to find since they only were used for a short while.