Are there many smog hoses on the 73'? Mine came with a 1972 351c in it, it's a 73' car, most of the hoses were vacumn hoses for the different gadgets. One thing for sure there wont be any smog stuff left on it after the rebuild.
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.