I think we may be placing the cart way before the horse with a discussion of EFI. There may be some simpler answers. An original 265 likely has an old Rochester or Carter 2-bbl., and although the car is "restored", do we even know if the carb has ever been rebuilt? Even if it has, modern gas and different driving styles and conditions could have put the carb "out-of-tune". Sounds like it's running rich. Might even have a sticking choke plate. Out-of-time motors can also throw smelly fumes. Or there could be internal engine problems that are causing blow-by, which is making its way out the exhaust. I would have a competent old-school mechanic look at all the potential issues that could cause emissions and/or mileage problems first before just buying EFI, transmissions, and cat-converters! Could be that there are other fixes that will allow the car to stay in its more-or-less original configuration and still solve the smelly experiences!
Thank you all for your insight. I grew up in the catalytic converter generation, and my first car (1965 Galaxie) was kinda smelly in my book. Not as smelly as the emissions exempt hot rods i see these days (i.e. it was a stock 352 V8 that was a boat anchor and very little else) but I just assumed he wanted the smell gone entirely when stuck in traffic.
I certainly don't think there is anything WRONG with an EFI setup. However, the owner makes it a point to tell us that it is "an original" motor and trans, and a "frame-off restoration". If there are some simpler things to be done to preserve the originality of this very period-correct car, I just think that looking into them FIRST is preferable to switching out lots of stuff - and unless we know exactly what is causing the issues, it's entirely possible that switching that stuff will not solve the problem at all. If the engine needs a ring job, and Sniper and cat-converter will not be beneficial.
All I'm trying to do is suggest that the things be looked at that we would have looked at when that car was 10 years old (before HEI distributors and EFI fuel systems and ANY kind of "R4" transmissions) - i.e., the basics of carburation, fuel burning, ignition, compression - the stuff that made them run in 1966, in other words, there may be a very simple answer and then an informed decision can be made as to how to fix it!