YOU'RE A SHARPIE NELSON!!
Yes..the two outer grooves on a Stude R1 Avanti's crank pulley and also it's water pump pulley, are never used in the factory R1 configuration.
( R1 a/c models have different setup)
The firewall mounted brake fluid reservoir used on '63-'64 GT Hawk's equipped with Avanti style disc brakes was first introduced as an option on Stude passenger cars in..
1) 1953....2) 1956....or.....3) 1961
Yes, the engine would operate the same...however the assumption here is that we are speaking of a complete 'as built by Studebaker' Avanti R1 engine...The chrome parts were part of that package.
Yes, there are a few different solutions for sealing the accelerator pump shaft on an R2...however, according to a very well respected Avanti carb rebuilder (NOT ME!!) the original seal has not been reproduced....Ed