One distributor yes (with 2 caps) but to adjust timing you set it for one bank and then the other. An interesting and somewhat weird setup that's for sure.

Here are pictures of one I had but never had running.
http://rides.webshots.com/album/560407755NLypFl

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-