All I can say about OBD1 is this...
If the chips could have been figured out in a way that were understood on how to actually get more out of the ecm (increase tunability), we would be able to swap in CCC carbureted 455's, 454's, etc., with modifications. OBD1 is very simplistic, but very effective, in trying to maintain top engine fuel efficiency/emissions throughout the operating range, while additionally protecting the cat converter. Unfortunately, that means by concentrating on fuel efficiency, performance would suffer. Sure, the fuel efficiency could affect some performance aspects along the power curve in a good way where needed, but in return, you'll have to give up some performance aspects. Additionally, the engines were generally designed for max fuel efficiency ahead of max performance. Reason for all of this crap? Bean Counters.
There's been a few places that had partially figured out the chips, but mainly they were just timing curve changes. Which helped, but were not a panacea. With the OBDII flash type controllers, tunability increased dramatically. It's too bad OBD1 didn't hang around long enough to make it economically feasible for someone to piggyback a "tunable chip" that the end user could tag onto the ECM to basically amplify or reduce ECM signals that went to the engine. If there were any widely and commercially available, I'm not aware of any.
Regardless, OBD1, when working properly, is way better at run-time on-the-fly adjustments than any human could ever be.
But if you take out the ECM, take out or disable ALL of it. You can't just do a partial. It's not hard, but previous posts explain the things needed to do it. Older carbs and vacuum distributor is in your future. If OG old school is what you want, don't install anything you need a computer for.