Larry - My 123 car was the same way. One of the pipes extended through the mounting plate, the other did not. Never had any difficulty sealing that particular connection, though I have certainly had my share of o-ring foibles. I can't remember how it is clamped - aren't there two bolts at either end? Or does it just have one in between the two pipes?
For parts & advice, let me recommend a place by the name of McCains. They're in Richardson, on Floyd Circle, behind TI. Both a service business and an over the counter parts operation. It's the kind of place where you could pickup a suction side filter, or have the manifold hoses replaced for fifty bucks. Whenever I've popped in for a small part - a few o-rings or service valve core - they've never bothered to charge me.