Approximate Cost to repair seals from blue smoke oil leak? on 1990 Chevrolet Blazer

This is really an '89 chevy s10 4.3 blazer but your list only went back to 1990. 210,000 miles otherwise good condition. Problem happens in the morning after sitting all night and when idling a few minutes. Smells in cab. Worried about carbon monoxide


Asked by for the 1990 Chevrolet Blazer
approximately more than the truck is worth