I have went over this swap idea in my head for 2 years now, and i have several reasons why i say a 3400 swap is a much better choice. I guess i will explain myself more.
Yes a couple of people have swapped ecotec setups into their nonecotec 3rd gens.
3rd gens used a completly different mounting system on the 2.2 engines than the 2nd gens did. Any knowledge gained from swapping ecotec into a 3rd gen does not apply to a 2nd gen. It will all be custom. Yes of course i agree with slow, the ecotec is an awesome engine and a more modern design than the old pushrod based motors. When i say a 3400 will stomp an ecotec, im talking about taking a stock 3400 and a stock 2.2 ecotec and comparing them. Yes of COURSE i could mod the ecotec to have more power than the 3400 (turbo/supercharge /nitrous) but guess what? I could do all of the same power adders to a 3400! When speaking N/A power this is a simple issue of Displacement. And weight is not a concern for me, a complete 3400 engine with all accessories attached weighs a little more than 400 lbs. I have no idea of the ecotec's weight but im sure its less, but not by a whole lot. This is pretty easy to infer from peoples 1/4 mile times and car weights.
Using an ODB1 ecu to run the ecotec is very possible. you need to consider that you'll have to come up with a new ignition system for the ecotec. You'll most likely have to use a GM DIS system off of a 2.2 and convert the ecotec to use plug wires instead of coil on plug. Then comes the issue of transmission, but that isnt much of an issue, just get a 5 speed trans out of a 3rd gen and then make up the custom mounting to install it in the car (which should be no problem since you've already made the custom mounting for the engine itself). you should be able to use the same axels between the 3rd and 2nd gen.
Yes its very possible, but at this time i would personally never attempt it for these reasons:
---------------- Cost ----------------------------
Ecotec motors/trans cost a lot more than the current 3400 and a transmission which you already have. They are also not as easy to find.
vs 3400:
For the cost of an ecotec motor, transmission, axels, material to make mounts, and Wiring ecu or alternatively software to program the ODB1 computer, one could have easily bought a 3400 engine, had a custom made camshaft for it, had head work, bought a transmission and rebuild it if neccesary, and make up a set of tubular headers for the motor.
-------Time------
Installing this setup is going to require several days if not weeks. You are going to need to put the motor in the car along with the trans and axels, measure everything up and get it aligned perfectly. Then you are going to need to design and create all of the mounting locations on the body for the engine and transmission support. Since ecotec engines generally mount at the top and bottom and not at the front and rear like 2nd gens this is no small task, Have a look at the 3800 swaps in 2nd gens.
Don't forget about the little things like, Throttle cable, Radiator hoses, Radiator, Fuel lines, and Heater lines! If you want to keep AC in your car, Best of luck to you!
vs 3400:
This swap is not new, it has done at least 50 times now, maybe more. The only custom pieces needed is the front motor mount to engine bracket and a new exhaust downpipe. There are currently at least 2 companies selling this mount premade. If you have a welder and some metal, its not hard to fabricate, set the motor in the car, boltup all the other mounts, check it for level, and just make the front bracket to attach the front mount.
Exhaust downpipe should be handled by any exhaust shop.
The swap has been done by many people in one weekend, and i think with good planning and parts in hand, the swap could be done in 1 day.
Throttle cable out of a 3100 beretta is a direct swap into the 2nd gen J and works perfectly.
---------------- Electrical--------------
You have two choices. Use the wiring and ecu from a 3rd gen with the same trans as you plan on using. You'll need to figure out how to delete the ABS, traction control, and Airbag code from the Ecu.. Don't forget about ODB2 using stricter emissions so you will also have to figure out how to remove this or use a 2nd O2 sensor simulator. If you want to keep your cars stock gauge cluster.. Forget about it, you'll have to find a way to mount up the 3rd gen's gauges in the car.
2nd choice: Use an ODB1 ecu: This is probably the route to go, programming these ecu's is well documented and pretty easy. Don't forget this will require changing the ecotecs ignition system. I'm not sure of how the ecotec engine sends timing info to the ECU but of course the ecu could be calibrated to whatever it uses.
vs 3400:
You need to pull the wires out of the loom that run to the DIS system because the coil packs are in a different location on this motor than on the 2.8/3.1. You'll need to locate a 3 wire temp sensor and connector out of a 2.2 4cyl motor as the 3400 has only 1 temp sensor location where the 2.8 / 3.1 had two.
----- My opinion ----
Basically it all boils down to Performance vs. Cost/Time for me. If someone just gave me a wrecked ecotec 3rd gen cav for free, then i would definately do it!!! I have a nice 89Z24 just waiting for a new heart in the backyard! But for my money and time, you just can't beat a 3400 swap in these vehicles. A bone stock 3400 using a bone stock exhuast system and stock 3.1 ecu code ran a 14.9 its first time on the track (stock wheels and tires also). Spend a little time on the motor, custom cam grind, nice exhaust, and take the time to reprogram the 3.1 ecu code for the larger displacement engine so it doesnt lean out in high rpms, i would not be surprised if you were running very close to the 13s.