I had a NEW '73 Country Squire 460 wagon that was a DOG until I changed the timing gear set to one from a 429. Removing the polution stuff made little difference until I changed the timing gear set. Sorry, '73 was not a great year for performance.
Remember, you can't just yank off the emissions stuff and expect the car to run right. You must compensate and adjust for what you removed. Not dificult but you must know what you are doing.