[mr0077]

Blackjack, I think Tony has the best idea...I just looked at mine and there is NO ROOM between where the S-tube would go and the fitting. Have you tried a 90 degree 3/8 NPT-to- swivel AN fitting on the manifold?
FWIW, be sure you have a PCV fitting in the line from the manifold to the breather, to regulate the air flow into the manifold.
My manifold has a "boss" that looks like it could/should be tapped, located between the carbs, pointing up and out on the drivers side, at about a 45 degree angle, that looks to go directly into the crossover between the front and rear plenums...if yours goes into that area, it should work just as well as (maybe better than?) the one at the rear of the manifold.
Good luck.