Howdy Chris:
There are so many variables to the answer to your question. For example, when I first got my 65 Ranchero, it had a 200 with the Calif/emission engine. I got it out of NM so it was pretty straight and little rust. I have no idea what it's life was prior to my getting it. It had the '65 C/E head, but all the stuff had been removed and the injector holes in the exhaust ports had been plugged. it had a '68 point type distributor with the stock, for '65 C/E 1100 Autolite (1.10 venturi) that was in bad need.
I was given an Autolite 1101 (What Luck!!! and I didn't even know what it was) I put it on without even rebuilding. What a difference!!! Was it worth it? YES!!! But it was free. All I has to do to get it to fit was to modify the allow adapter plate by tapering it to clear the butterfly. The mounting holes were already slotted. As I said, a previous owner had already changed the distributor to a '68 with centrifugal advance, So I ended up with a better stock parts upgrade for an afternoon of tinkering and tuning.
I don't recall what upgrade you've made, but, in my opinion, a carb upgrade is worth it- to a point. Ideally, the carb should be part of a balanced engine package. Each part should compliment all the other. My suggestion to you is to consider your whole engine package goal and then buy/accumulate parts and do mods that move you to your end goal. The more you do the less it costs(watch out for Murphy), the more fun it can be and will be most rewarding in the end.
Sorry for the dribble. There are very few simple answers and they will likely generate more questions.
Adios, David
