Want to Buy Dallmeyer Pentac 8" 2.9

I am looking for a Dallmeyer Pentac lens to mount on my Super D for portraiture.

Great choice. I have one an a 3x4 RB SuperD converted to 4x5. It just reaches infinity perfectly on that camera, and can focus quite close as well. I tried a lot of lenses on that rig, and that one worked out to the best. Good luck with search. Ebay UK can be useful for finding these.

I'm trying to install it on a 4x5 super D. It should reach infinity and also clear the mirror box.

It will definitely clear the mirror box, since it does on my 3x4 RB. Infinity: hard to say. It just makes infinity on my 3x4 RB, with a home-made front standard and lensboard. The front standard is in the same plane as the stock one, but solid (not recessed) so the mounting face is about 1/4 - 3/8" further out from the film plane than stock. Then the lensboard is about 1/4", so probably total of 1/2 - 5/8" more extension than stock, if that helps. You might need a slightly recessed board, not sure what the front-standard-to-film-plane distance is on the 4x5 RB. good luck

-Ed