Well, let me check my notes and see what I can remember about the 289 engines..
I will assume that you are talking about the 289HP model, which is similar to a standard 289 except the main bearing caps were thicker. They used the same size ports, CC's and valves (except for select castings) as the base 289 heads. Main difference were slot guided push roads, and screw in rocker arm studs. They also used a HD connecting rod with 3/8" bolts.
The 289HP was produced from (I believe) 1963 - 1968.
Heads ranged from a cc of 49.2 to 54.5, depending on casting numbers. The 49.2 cc heads had 1.67/1.45 valves, while the 54.5 heads used 1.75/1.45 valves.
The highest factory rating for the 289HP was in the 1967 Shelby GT 350, and had an engine code of "2". It was rated at 306 HP and 329 ft/lbs with a compression ratio of 10.0:1.
The "standard" 289-4V engine during the 1963 - 1967 period had a rating of 225 HP and 305 ft/lbs, and had engine codes of A-C. The 289HP engines (other than the Shelby unit) had a rating of 271 HP and 312 ft/lbs.
Hope that helps a little..