1963 catalina engine question
 

Would the presence of a 'single exhaust 2 barrel carb' 389 automatic trans engine be an indicator that it would be a '230 horsepower economy engine' ?

No, you can't go by that criteria. My 65 came equipped with a 389, 2 barrel, single exhaust, automatic transmission and was rated at 290 hp. The same engine with the compression reduced to 8.6 was rated at 256 and came with a manual transmission. It's a matter of compression ratio.

What is the engine code? Most 63 Catalinas had the 267 horse engine. The low compression engine had a rectangular stick on the vale cover that said REGULAR FUEL ONLY.
there should still be a mark from it on the cover even it it is long gone.

21L & 20L Were 230 HP Grand Prix in 1963 came standard. all others would be extra cost item on the 389 exhaust

I bought a 64 2-door Catalina in 1971 from the original owner that only had 15,000 original miles. It had the low compression 389 two barrel regular fuel single exhaust engine and a Roto-hydramatic trans. I think it was rated at 235 hp. No sticker on the valve (rocker) cover. The carb was the small diameter like the size found on the center on a 65 and earlier tri-power. A few years earlier my dad sold his 64 Star Chief. It had the high compression 389 two barrel premium fuel single exhaust engine and a Super Hydramatic trans. It was rated at 283 hp. The carb was the large diameter like the size found on the center of a 66 tri-power. A friend of mine had a 65 2-dr Catalina with the high compression single exhaust 389 two barrel (large diameter) premium fuel engine and Turbo 400 trans rated at 290 hp. Based on this the 389 economy low compression engines (regular fuel) had the small diameter carb while the large diameter carb 389 high compression engines used premium.

According to the 1966 Chassis Parts Catalog, there were a ton of different engines available in 1963. Here is the chart.

What would have been the original make and model of the 4 barrel carb on a 1963 389 Catalina ?

Carter AFB