1965 Barracuda 273 rebuild...intake code?

The heads are correct for a 64 and 65 273 but the block casting (2806030) is listed as a 67-74 318 casting.
#2806130 is a 273 casting for 65-69 273.
Sometimes the numbers are hard to read.
It sounds like you have a mix/match of parts there.
Here's picture of the block casting number:
Block casting number.jpg