As far as I know michael is still away attending to family matters, so I'll weigh in on your question. Yes, ihon does sell the 0-7448 and they set it up with manual or auto choke as per your preference. Dandy carb, but your wallet will be a little lighter. The older list number 2300 models are pretty straight forward to rebuild. This tech subsection has plenty of info and pictures to help you out. The list number 2977 was originally installed on 266 engines, but no doubt a number of them have migrated to 304's and I imagine are doing a fine job. The other list number corresponds to a carb that would have come on a 1970 model 304. Its probably 6 of one, half dozen of the other. I think either carb properly cleaned, kitted and tuned would work well for you. With a gun stuck to my head to pick one or the other or else, I'd service the 4595. The Holley kit 37-1543 is what you use for either carb. It makes for a good learning experience. And afterwards, if you're not happy with the results, you haven't lost much.