Howdy All:
It seems FoMoCo changed from 1.5" carb hole to a 1.75" carb hole sometime during the 1969 model year. Heads with casting # C9DE-C,F,J, & K all had 1.5" carb holes. The C9DE-M head was likely the first head with a 1.75" carb hole. This is also the first large volume, flat-topped intake log. Several later castings used the large volume, flat-topped design too. All DXXX and EXXX castings have a 1.75" carb hole. Some D7XX heads have the larger 1.75 intake valves and induction hardened exhaust seats. All D8XX and later casting have 1.75" intake valves and hard valve seat inserts.
Hsfd202- you can use your Autolite 1100 on a later head even though the carb bores do not match. You may have to elongate the mounting holes in the carb to match the mounting studs on the head. The later head is your best choice for all the reasons Rocko listed, Just know that your have to compensate for the two differences I described earlier; chamber volume and head gasket thickness.
I like the Autolite 1100s, too. They are quite simple and easy to work with. The accelerator pump system seems to wear out first, and so poor transitions are my first indication that it's time for a rebuild. Cleanliness is key on assembly. Isolateing it from too much under hood heat also helps avoid vapor locking and percolating problems.
The Holley #1946 is a more sophisticated carb, and consequently, more complicated. They are a little more worrisome to work on and to get "just right". It became more encumbered with EPA electronic feedback mechanisms each year. Running right, it should give better idle, transitions, economy and power than an Autolite 1100.
Rocko- Our book is aimed at exactly the hobbiest you described. It is more of a down-to-earth, find the best OEM parts, simple modifications, for the back yard hot-rodder. It would be nice if we had money to throw at our toys, but we don't, so we get creative, and try to get the most out of what we've got. I think it would be right up your alley.
Adios, David