454/4l80e/203/205 - Which computer and harness?

Hello, Starting from scratch here. Building a '70 Blazer with a 454/4l80e/203/205 setup. Tranny is a 1995 4l80e 4x4. Currently have a standard Q-Jet and manifold on the 454. Looks like the throttle bodies and intake manifolds were used for a number years, so that's easy, but several different computers were used. I do not have access to a donor vehicle at the present time, just the local salvage yard and the online sales sites, so, what computer would be best for the setup and if sourcing a stock wiring harness, would you need one out of a truck with a 4x4 4l80e, or would it be better to go with a stand alone such as those made by Howell or LS1 Wiring Harnesses. Thanks for the help, I'm sure I'll have more questions as I dig into this, but have to get the parts first.

Pre made aftermarket harness are nice. But most of the guys around here build them from JY pulls. Just depends on your time and money. You will need at least trans wiring from 4L80E as it's differant then 4L60E. The rest of harness is same.

Best choice would be 16197427 from 94-95. Note that the PCM could have other numbers. Note that chip in memcal has different bin/calibration in 1995 for the trans, it has PWM TCC lockup. Differant torque Converter.

Thanks for the input.