After looking at my 1966 parts book, I only see one Hemi distributor listed for the 66 R & W models. I took a digital picture of the page that lists all of the various distributors for all of the engines in 1966 and posted it below. If you can't enlarge it to make it easy to read, let me know and I could e-mail a larger version of it to you if you wany it. By the way, I did not find a listing for the other part #2444358, so unless I missed it, it doesn't look like it's a 1966 correct part number. :dontknow:
Here's what I found on the 426 unit. The first listing is a complete distributor and the second is a factory replacement unit, that was sold minus the cap and rotor.
Richard
#1
Models used on - R, W, with 2 4 bbl carburetor, without C.A.P.
Engine cubic inch - 426 Hemi
Transmission type - all
Breaker points - double
Distributor id, stamped, complete unit,
2642482 - IBS-4006P
#2
Replacement assy's id, partial, less cap and rotor,
2642484 - IBS-4006PS