I have done the on3 on an 86 fox , also an HP setup on a 94 cobra. so i have some exposure to what you are doing. you will need 60lb inj to make max power, use Siemens . you will need a lot of pump, 340 L min and you may still run out, I use twin 255s, then its -8/-6 lines and new rails. stock cam works well, standard throttle bodys with egr gone works well. Head studs,,I use them, what I found was right when you think the timing is right I would blow the head gaskets,,,so start with timing WAY reduced , like 15degree, get fueling rich under load. start there. Get a GOOD wide band or you will blow it up leaving the driveway. I know
OHH, and then find all the rest of the weak parts, axles ,trans, driveshaft , rear suspension bushings, ect. LOL
I would really recommend an aftermarket ECU, the old ford stuff is obsolete/unreliable and hard to find. remember they only built the ECUs for the 94-95 then went obd2 in 96 and thats another thing.