Advanced Engineering Tech - 5.3 ECM help

My 2002 Avalanche has finally racked up 230,000 miles and even though I haven't had any problems at all, the dependability is questionable. So I'm swapping in another motor and rebuilding the old one to put in my 1974 Jeep J20 baja truck.

My question is can I get a used GM ECM to run the old motor temporarily on either a stand or in the Jeep until I can get a FAST system? I think I can just plug a factory ecm (100 bucks on ebay by the way) into some power and that will get me running enough to check leaks and tolerances after it is rebuilt.

Is the FAST system worth the $$$$$$? Is there a cheaper option?

Thanks

I got a 2001 LM7 5.3L for my '84 Trans Am, then got the matching computer for $90. Then I contacted PainlessWiring about a harness, and they have this deal where when you buy the harness, you send in your computer and they will remove the VATS for free.

Make the harness you have a standalone harness and you can then run the motor with out it being in a vehicle. Just do a search and you will find lots of info on the subject.

Maybe post this in the correct forum?? There would likely be more response[s] in the hybrid section...