276 flathead test drive big improvement.........but?

[51 MERC-CT]

Originally Posted by 36tudordeluxe

Have adjusted idle mixture screws to a lean setting as described by Edelbrock. Out looking for a timing light to help solve the problem, the one I have is outdated and missing the spark plug adapter.

Now that you have set to a lean setting and it is running, adjust for best vacuum and idle.
If the spark plug adapter is what I think it is, it's nothing more than a metal conductor that fits between the plug and plug wire to provide a spot to clamp the sensor. (nothing fancy and probably can be made up out of available materials.)