thanks dolt, the heads are from a street kit, with the same numbers as you quoted. the ones I found have 5000 miles on them and I can get them for $600.00. what do you think.
Tough call.:sd The CNC heads are decent and certainly a step up from the OEM heads but not sure if the step up is worth $600 when, for about the same cost, you could have your heads fully ported with larger valves, etc.
Without seeing the heads, I can't say for sure but I would probably have them broken down, cleaned up and all carbon removed from the chambers, valves lapped in to the seats, new guide seals and I might even have the "high performance" valve springs swapped out for the OEM beehives. I don't recall the seat pressure on the springs in the CNC head but those heavy duty SE springs can be a source of valve train noise.
I am fortunate to live very near one of the best head porters in the country so it would be very easy for me to have a set of OEM heads fully ported heads with 1.94" intake valves and 1.630" exhaust, etc., etc, for $750, so I would pass on purchasing a set of SE CNC heads for $600. However, you may not be as fortunate and, like I said, the CNC heads are a step up from your OEM heads and the price is reasonable. However, I would not just bolt them on without checking them out as outlined above which will add a bit to the cost.
If you haven't done it already, I would suggest that you replace the head gasket with a .030" MLS head gasket like Cometic and yes, the later intake flanges will be required as well as a new set of performance exhaust gaskets.
The only other thing I would suggest is that you do a compression test before the exchange just to verify actual compression. According to my calcs, you should see about 190psi; a good place to be. However, you might also machining the heads for compression releases, installing them and using them. Not a "must do" but will extend battery and starter life at the compression level. Additionally, should you ever increase displacement to 95" or 98", you will likely need compression releases then.
Like I said, tough call but not mine to make. Sounds like you are prepared to spend some money for heads to improve the performance of your build. So, the question for you is whether or not to spend the $600, plus the cleanup cost for the CNC heads or spend a bit $700-$900 for a set of Stage II or III head from a reputable porter. JMHO.:bigsmiley10:
Also, I can't finish without adding that increasing displacement is the most cost effective upgrade to any build. If I were in your situation, I think I would go all in and bore to 98" as part of the upgrade. :s