for 1990 RC? my plans are headers/exhaust new cold air intake may try some e3 plugs and firecore wires maybe a shift kit for my lovely over drive trans

I'm not sure there is much you can do. I've never seen a hotter ECM for a TBI truck. There is probably a custom tune shop somewhere. Maybe a Shelby Dak ECM would work if you could find it.

Dual exhaust, K & N air filter, good plugs, wires, cap, and rotor, pretty standard easy upgrades.

Is it a 318 or 360? How many miles?

What are you looking to do with it, mud bog, street race? Personally, I've always felt power is in the heads and cam. How much do you want to spend?

No hotter computers unless you swap a 360 computer in place of a 318 computer. The 360 computer has a tad faster advance curve. Make sure you ad a o2 sensor in the new exhaust system..

just cruzin and towing its a 5.2 as for miles the odom stop working before i picked it up, i am the 3rd owner of the truck you can say there is the buyer in the aug. of 90 then he sold it to the 2nd the 3rd picked it to flip it but had to move it asap and thats when i snaged it lol

360 computer in my 318 Ramcharger ran ok, ate more fuel. Add 360 throttle body and then it has a low end bog. This is with an added 10* advance. Put the 318 injectors in the 360 TB and it's really lacking power. Haven't swapped back to the 318 comp yet. That's this week once we thaw out again.

As far as something tuneable, you are down to something like Megasquirt. No factory help for these dinosaurs..

E3 plugs are a scam. Skip them.

the maker of firecore wires says they are decent, and he runs them on his own rides.

I ran them on my Hemi, and saw no difference over my Autolites. I put them on my 6.0 Surburban, and they miss. So I am sticking with and going to recommend Autolites from here on out. That is my 2013 stance on them.