I just purchased a set of heads on ebay, big block 820 casting, they need reworking, and in the pic the valves were pulled out. he says the valves measure 2.06 and 1.72 yet the valve seats look like they have been cut out for 2.19. can they saftely be reworked if they already have been cut once?

 

Most likely they can, but you won't know until you get them and have a machine shop look at them. You may have to have seat inserts installed if the job wasn't done properly.

 

BTW, since those are pre-unleaded gas heads, hardened exhaust seats and valves are a pretty good idea, anyway.

 

i thought that in 1970 and later was factory installed with hardened valve seats?? They are open chamber heads.... Not 840s... or maybe I am wrong?

 

1975 & later.