[scicala]

There is a tube that goes across inside the bottom of the intake manifold (exhaust crossover). Then the brass elbows press into that tube. The manifold was threaded by someone along the line. You can't just put the brass elbows into the intake without the tube, or the exhaust gasses will go into the choke and destroy it. The heat tubes are available if you don't have on in the manifold now.

Sal