O have a set of C heads I am thinking of selling how much re they worth?

 

They are good heads but not worth lots of money like D heads. I believe there are some are big valves and some are not. The problem is the weight which causes shipping to be very expensive. You might want to post where you are located.

 

C Head casting 394548 80cc 2.000, 2.072" 1.625" 67-69 400/425/455's [except W-30 and most Hurst/Olds], including 1968 H/O with A/C. Valves commonly 2.000" and 1.625", but Toronado and 442 [except Turnpike Cruiser] heads had the larger 2.072" intakes. Presumably the H/O with C heads also had the large valves. Shallow spring seats. No hard exhaust seats. On 1967 engines, RH head will have the engine ID stamped into the front. Correct for 67-69 442's, even 68 H/O with air. Heads for 1967 W-30 or California cars had the A.I.R. passages [that boss on the exhaust port] drilled, tapped, and plugged. Some '68-9 442's with auto trans may have had small valves. This is reputed to be the best-flowing head, and is still fairly easy to find.


per https://oldsjunction.classicoldsmobi...sfaq/ofhed.htm

 

Best thing to do is take a picture of the stamped number on the end of one of the heads and show it to us.