1965 Barracuda 273 rebuild...intake code?

The Commando 4bbl block is the same as the 2 bbl, only the pistons differ, so other than the casting# being the wrong year, your block is "correct" for a Commando. 4bbl cars had a special exhaust with rear resonator. It is still a single exhaust, but the rear valance has a rectangular slot (driver's side) to clear the resonator, so if your body has that it was an original 4 bbl car. I don't recall if all 4 bbl or a special model (D-Dart, HiPo, forget). A member here in Europe has one and has posted all the info.

Some wonder why they didn't make it dual exhaust. I read that they tested both and found the single exhaust gave more power, similar to the 4-into-1 exhaust conversions that were popular on 1970's motorcycles. One company reproduces that complete exhaust, I recall ~$750. Some have installed a dual exhaust, but you must fab a cut-out in the transmission cross-over on the right side. One exhaust company will do that for you if you ship it and buy their dual-exhaust kit. Dual exhaust might look better to the casual public, but those in the know are more impressed with the resonator HiPo single exhaust.

BTW, if you get the domed HiPo pistons, a racer's trick was to install them clocked backwards. That is because the wrist-pin is slightly off-center, so changes the stroke per crank angle motion. I don't know if that applies to the Egge domed pistons.

I have a few HiPo pistons since I bought a HiPo engine locally for $100, but it sat outside with the V up so all pistons were rusted seized. I got all out by beating, but some were damaged (others questionable). The block would have needed over-sized pistons anyway, unless one were to sleeve all cylinders to use standard-size pistons. The block isn't special, but at least the crankshaft and rockers are good, so worth the price. Too bad the guy used the special finned valve covers (rare & valuable) on another engine. If anyone needs a 1965 block to be correct, I'll sell it cheap if near Sacramento or off I-99 or I-5 my next trip to LA or San Diego to visit kids. OP is in TX, so shipping a block is $$$, but small parts, like the pushrods (longer for solid lifters) I could mail.