Dropped off the original exhaust manifolds to a friend's shop last week. He sent them for a few rounds in his block tumbler using some steel shot. Gotta say the exhaust manifolds came out looking great. Now to spray them with a high temp clear and keep them looking this nice. Here's the before and after shots and some pics of the tumbler he uses for cast iron parts cleaning.
How they looked before being tumbled.
A look inside his tumbler as he just finished cleaning a block.
The steel shot that he uses for cast iron clean up.
The tumbler itself. These things are cool.
And the exhaust manifolds after being cleaned up.