MegaSquirt | Engine Management System | Electronic Fuel Injection - DIYAutoTune.com
With what you've described, the Vortec is a running engine with a good harness and sensors. If that is the case, then for less than $600 grab a MSII with the relay board and cable.
You will never need to burn a chip and hope the chip PROM was good, not just functional (good is the enemy of better and best.) You can eliminate emissions functions or keep them OR, the best part, keep them on the engine and turn them off until you head to the inspection station. Grab a wideband O2 sensor and then you can tune for mileage much better than the stock ECM ever could. Basically you can tune for AFR ratio's better for mileage in cruise condition and better for torque and horsepower in performance situations.
If you use a 97 4L series transmission, then an MSIII is capable of running the engine and trans. I assume your TBI setup is running a 2004r/700r4 old scholl mechanical other than for maybe road speed and TCC - the MSII can handle both.
$600 bucks sound like a lot of jing, but how much are you going to spend in ECM chip programming just to get a stock running unit.
I want to be sure that I sound respectful to these guys that have offered advice as I've followed alot of their posts for quite some time and these guys know their poop, but...........I think that if you start adding up prices on swapping parts from the two different engines and/or buying parts to do the swaps, and then compare that price to the Megasquirt pricing you'll find the MS cheaper or at least comparable. And also consider that you can swap in the running Vortec which is way more motor than the TBI long block.
And the best part is the datalogging and tunability - NO comparison. FYI - the software and firmware is FREE to everyone, and system is able to handle boost/nitrous control and timing control at the same time while still being a daily driver.
DIYAUTOTUNE's support is great also. Good luck. Sounds like a great swap that I'd love to try.