[TR] TR4 vacuum port

[Allen Hess]

I've had occasional but persistent oil fouling of the #1 plug for a  
few years and a hotter plug in that cylinder has helped. Symptoms  
point to worn valve guides. I was going to get a vacuum gauge and try  
to do some more diagnosis. However, I don't have any manifold vacuum  
port other than the advance line in the carburetor. And I'm not sure  
that would work as it lies beneath the throttle plate.

The intake manifold has two bosses cast into the balance tube which  
certainly looks like Triumph was thinking about this but it would have  
to be drilled and tapped. Anyone else been down this road?

Allen