Russ,
I understand that the later 235 blocks were drilled for the hydraulic lifter oil passage no matter if they had the solid or hydraulic lifters installed. If you are contemplating replacing your solid lifters with hydraulic, you need to confirm if your block is set up for hydraulic lifters.
You will also need to change your cam, I believe, as the cams are cut differently.
The head will work either way.
Kurt
