Frank-
Dual setups require synchronizing linkage- I have some pics of various setups, but no dimensional info. I suggest you disassemble and check each carb to see if everything works correctly, and to see if the full power metering screw is set identically on both carbs. If one carb has worn parts or is set incorrectly, you'll have an omigodnightmarehorrorshow on your hands. It looks like Brown may have followed the Reece version Fish for a pattern- the full power adjustment screw doesn't rely on shims. You unscrew a plug in the top of the carb body when the pickup arm is at full throttle, and use an Allen wrench to move the screw in/out. Reece made the 2 BBL Fish, along with some sidedraft models in the late 60's. Motor magazine had a writeup in the March 1st, 1969 issue- it and some other info is posted at
http://mk1-performance-conversions.co.uk/images/reece_review.jpg .
You need a tool to set the cruise range (easily, anyway). You can make it from a piece of 1/2 x 1/2" bar stock about 3" long and two 3/16" bolts. Find the exact center and measure out 5/8" out on either side. Drill and tap the holes for the 3/16" bolts. Now comes the fun part. The gauge has to center on the OD of the carb, so at 1 1/4" out from center you have to either set pins (edge of the pin at 1 1/4"), or use a 1 1/2" holesaw to notch the bar, then mill out the depth of the notch between the outside cuts. One of the bolts is 2" below the top of the carb, and the other is 1 9/16" below- this sets plate angle as you turn the throttle shaft. You measure from the top of the carb to the end of the bolt, so this is why the material between the holesaw cuts has to be removed if you go that way. One picture is worth a thousand words- I know.
