I usually tape the surfaces


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

For cleaning any residual point from the block bellhousing mating surface, I simply use some ‘Brake Kleen’ or similar product on a paper towel.  Paint comes right off.

Lorena, Texas (South of Waco)

I haven't taped one off but I do avoid spraying directly on the mating surfaces. That's with paint. I don't have a big enough oven to do a block or transmission. Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

So a follow-up question to this, do you mask off the mating surface on the block to keep that clear of paint?  I am sure paint is thinner than powder, but I don't recall seeing this done

Thanks all for the your input.  I think the consensus is that it probably won't cause issues but there is always the chance it may.  I have all winter to work on the little details like this before it goes back on the road, so really no excuse aside from laziness not to.

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Just tell the Powder Coater to not powder coat those areas.
They have a product of sorts that will stop the PC from sticking.
I don't know what it's called
Jim

Any paint or powder coating needs to be removed from both the block and bellhousing mating surfaces.  It only takes a slight mismatch at those surfaces to have the bellhousing off ever so slightly which in turn makes the transmission not exactly in line or parallel with the crankshaft.  In that instance and using a standard transmission, there can be some transmission shifting issues or a vibration.  All engines leave this shop with the blocks’ bellhousing flange thoroughly cleaned of any paint or residuals.

Lorena, Texas (South of Waco)

I would remove it. It may not cause a problem but I am anal retentive about a lot of details.

Bolt up the bellhousing, put a dial indicator on the crank to make sure everything is aligned and then also check the flat area where the trans bolts and see how far it's out I'll bet not it not over .001"

56 Vic, B'Ville 200 MPH Club Member, So Cal.