so im getting a spare v6 harness ready to get a 3800 and 4t65e installed and i cant find any information (that still makes sense) about adding a power distribution block to the 84 so i dont have to run everything off the starter (which doesnt bother me but ive heard it can cause issues)
and ill figure out the mounts when i have the money im just trying to get as far as i can without spending more than 80 bucks which so far is going well

I have an 84 that I swapped. I believe there are only two switched ignition leads to work with which is pushing it for the additional loads the 3800 engine and trans needs. I went with a sealed fuse relay box mounted close to the battery that supplies power to the fuel pump, engine, PCM, trans and ac compressor. Turned out really nice and the power is no longer needing to travel through the ignition switch. All Fiero harness wiring modification was done after the 500 and 203 connectors so the main Fiero wiring is unmolested. I searched for hours/days to find the perfect fuse relay box that fit my needs. It was made by GEP I believe. I can get you the model number if you want. It is not pre wired so terminals need to be crimped but this allows a clean custom install.

While I never did an 84 3800SC swap. the wiring that was used on my personal swap is best described as Grand Prix. Just moved the entire Grand Prix power center (fuze box) ,harness and all to the battery location. Fed a heavy wire from the battery to the power center. Then put in connections for a few things like the speedometer interface fan etc. We left the connections to the instruments as is. It was a very simple install as most connections were already made. The only compromise was that the PCM had to be located behind the drives seat (in a PCM Tray). IMO good location and Cool, All this may work on any Fiero.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

I used this style motor mounts for both my swaps, one hole will need to be slotted over 1/8-1/4". Easy peasy

https://www.amazon.com/Univ...-8lkmWayo5GeVVvFvUbp 1cCjXQLUuW8W3HIka8BVRqN0aTgGehQ0o.39xF6dImimsHLkCwgkBUU5KODvCWkYQzLYexn0Xc-wE&dib_tag=se&keywords=ls+motor+mounts&qid=1752157855&sprefix=ls+motor+mounts%2Caps%2C1340&sr=8-54&xpid=9AYD8cgUwBddD

shem