IS THE ENGINE RUNNING OK? IF SO BETTER LEAVE IT BE. EVEN IF YOU COULD BYPASS REV LIMITER IN ECM.
THE ENGINE STILL HAS A RPM LIMIT AT THE POINT WHEN PARTS START COMING OUT. BUT IF ENG. IS NOT RUNNING RIGHT ON THE ROAD THAT IS ANOTHER CASE AND NOT REV. LIMITER RELATED.
Retro-fit with quadra-jet (400CFM should be more than enough)and dual-points distributor from a '65 barracuda formula 'S'. Dual glasspacks would be cool too. Or you can google 'ford probe performance' and see what shows up. I'm sure there is some company that sells modified PCMs for it (although illegal for on road use most likely).......... I resent that TRIX are only for kids.