1....Should be easy to disable the scoop long enough to test, just pull the filter if necessary and plug it up with cardboard, rags, whatever...........
2.....Fer Lord sake, get your wheel degreed this is EASY. Use a piston stop. Surely you know this with that build
3.....After you get the timing straightened out I would for sure experiment with vacuum advance hooked up.
4.....I know some of these cars used a seal between hood and rad support, you might take a really good look at airflow through the rad
