I just installed a H/W 5200 yesterday. I have a '66 coupe that was all stock until last week. I swapped the head for an E0 and added a new cam and DS-II. While I was at it, I thought "Why not?" and added the 2v carb, also.
I got it from Stovebolt and an adapter from Clifford. The clifford adapter orients the linkage to the right side nearest the gas pedal bellcrank, which isn't the best setup for the carb but works if you're not gonna make alot of hard turns, so I hear....
I spent alot of time trying to figure out where to get a linkage. I couldn't find any parts locally.
The stock linkage adjusts out an additional 1/2" to 1". I added a small 2 1/2" x 3/4" piece of aluminium to the linkage on the carb. I drilled 2 holes and attached it with bolts thru the same holes where the linkage studs are in the picture in Jaymers post above. This effectively extends the carb linkage out 1 1/2" to 2" or so.
Then with stock linkage still attached to the bellcrank (extended it out as far as it would go) I held it up to the new aluminium arm to gage where it should attach to allow full range of movement for the carb when stompin' on the gas. I used my son to stomp while I watched the bellcrank and linkage. I drilled another hole where I thought it would work, attached the stud, snapped the old stock linkage on to the new arm and Presto....I had a simple solution.
I had my son smash the gas pedal to the floor while I watch the linkage to confirm full range up to WOT and that it didn't bind on anything. Worked like a champ. Throttle return springs back down on the exhaust flange. Test drove it for the first time today.

Worked great.
I'll figure out how to post a pic so you can see how simple a job it is.
Here's a link to a similar job and lot of great info on the "engine" link from this page:
http://www.albertpenello.com/mustang