I am looking to increase the vacuum pressure going to the power brake booster on my 66 drum/drum setup. The brakes are very hard to press. I have a 289 'c' engine. Right now the vacuum line tees of a smaller line going to the transmission. When I take off the air cleaner, I see lots of bolts that look for mounting purposes. I only see the one hole used for vacuum. Are there others that I can not see? What is my best way to increase the vacuum pressure?