Henry, My vote is for a 1 inch spacer vs a 2 inch. I put a 2 incher on my edelbrock intake and edelbrock 1406 carb, it really throughs the geometry of the linkages off. I used a pholic (spelling??) material as thats what Edelbrock recommends.
HOWEVER, I think you post is relative to bolting a Edelbrock 1406 carb to an GM Q-jet intake. My 2 cents, don't. Either follow Joes excellent advice about getting an Q-jet carb or get an dual plane intake compatible with your 1406 AND get a 1 inch pholic spacer.
I believe GM used a thick gasket (about 1/4") between the intake and Q-jet carb. I wouldn't suggest additional spacing with the Q-jet setup. Good luck.
