The two aluminum spacers.  Move the two rear ports forward on both sides the same amount to look normal.  You are going to need space for the plug wires and boots on top of whatever cap you use, so use a cap with wires in place and see just how far you would need to slide the Webers/carbs spacer on the long spacer forward to clear, and see if it is possible to blend that amount to the heads.  I have moved ports a lot on spacers and blended them, not ideal, but it could possibly work for you.  You can remove a good deal of the carb spacer bosses, also without ruining their integrity.  Joe-JDC

JDC

Going with Charlie's plan A first. Plate aluminum is at the machine shop.

Well, the blocks will do the trick. I need to massage them a little to make it more attractive but at least I can get the distributor on and moving freely.  Still looking for the right distributor, may just have to use an old 292-312 stocker. Can't find a Mallory 387A anywhere.

Just purchased a 57-63 Ford Distributor with combo mechanical and vacuum advance. Should do the trick.

387 A is a Y Block marine distributor, if that's what you want E Mail me $100.00 plus shipping (this is a dirty used part)

Liqu@aol.com

Thanks Cliff, should clean up nice.

I have a few more

Nice collection! 

Well, the Mallory distributor isn't going to work. It's just as tall as the 57-62 Ford distributor which doesn't quite clear the intake plenum. I guess we are forced to use the stock 368 dual diaphragm (never knew there was a G in that word). Now I have two vacuum advance lines to run into 8 single throated carbs. Figure that one out!
FYI the height difference is in the base of the distributor where the points are, not the cap. Diameters of all three are almost the same.

Mallory has a crab cap that is a lot shorter.

https://www.ebay.com/itm/Mallory-Crab-Distributor-Cap-plus-Rotor-Fits-Fords/143714160675?hash=item2176081023:g:ZnkAAOSwvJFfToKn