Well a brand new factory fresh 289 2v was rated at 200, the 4v rated at 225. So, if you want to use these numbers as a reference, it will give you some idea. Understand that the way HP numbers are measured have changed over the years.
If you compare the 71 302 2V to the 72 302 2V the 71 was rated 210 hp while the 72 was rated 140 hp. Main difference is 71 was engine crankshaft with no accesories or exhaust system. 72 was SAE net at transmission output with exhaust and accesories.
There was a slight change in 72 lowering the compression from 9.0:1 to 8.5:1. This would account for 5-10 hp.