Connect a vacuum gaube on the port that's usually used to supply vacuum to the windshield wioers- - - -full manifold vacuum, not ported. Run the engine at a constant steady speed, maybe 1500-2K RPM. If the vacuum drops steadily and the engine loses power or stalls after running for a time, there's an exhaust restriction. Find it and fix it.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!