ok, i was wondering if anyone had a link to a compression ratio to horsepower calcualtor or could explain how c.r. relates to hp? i understand that 289's have 58cc heads with a 9.3:1 c.r. which seems low. id hate to give anything up by buying 64cc late model heads, seems like it would really hurt things. even if i bought 58 cc heads, i wouldnt be gaining any compression. is the only way to gain it to mill the heads or change pistons? i wouldnt be concerned except that im under the impression that compression ratio can really boost hp levels