After weighing my options, and reading that a #'s matching car is worth up to $10,000 more than non-matching, I have decided to rebuild my 326. Does anyone have any proven combo's that will give some good HP? Does anyone know the difference between the 140 & 141 heads, one website says that the valves are 1.94/1.66 and the base 326 has 62cc (9.2:1 compression ratio), and the high output has 52cc (10.5:1 compression ratio), and another website says that the valves are 2.11/1.77 and has 72cc for both the 326 base and 326 H.O.?? I don't know if I should rebuild my existing heads (#140), or get new ones (I can get #62 heads that are already rebuilt for $400- they are also suppost to be 2.11/1.77 valves and 72cc). I put Flowmaster dual exhaust, and it has a Edelbrock 600cfm carb.