Jim Brierley mentions in his "building a mild engine" article that the 216 Chevy intake valve is a viable option. The size is 1 and 11/16" with 30 degree seat angle. Not too sure how easy they are to find.
Smitty, ours came from Skokie Antique Auto Rebuilders in Skokie, IL Dont know the brand. Larry at So. Fla Crank & Machine did our rebuild. Finished recently and put in a restroation that is 40% done, not road ready as yet.
probably the easiest way is to buy ones that are made for the model A. there's a place in texas that sells 1.7" intakes. piranio's ,www.modelaparts.net or 940-382-2742. you can get the complete kit for the A.