Reply To: RPH Welch Plugs?

[DAN ANDERSON]

{content}Well FrankR that close! The back half (all of OMC die cast blocks) were pressure coated. Put in a pressure cooker looking vat. Then pressure was applied to force the paint into the pores of the aluminum. This was only done on the water cavities half of the block. The front half was not deemed necessary. It was don’t before machining as FrankR mentioned.
I believe these would have been OMC powerheads because they quit doing this before the end of OMC (cost savings). When powerheads were sent out lots of dealers did not paint the new powerhead for the customer. Warranty would pay to paint & allow for paint, but you had to ask? Left a bad experience with some consumers after they got the engine back. When the plants moved south the assembly procedure changed & all assemblies got painted black before final rigging.

Dan in TN