Zippy - how did you find your vacuum leak under the intake, and what did you need to correct?
440, oe heads, aluminum intake.
After trying carb cleaner and so on, which didn't work, decided to try water.
I tried a hand spray bottle, got me nowhere, not enough volume, couldn't really aim it where needed.
I then tried a garden hose flowing under the manifold...that showed the leak very quickly.
The repair was to open the bolt holes slightly since they were preventing the manifold from sitting down quite far enough,
and I also started using paper gaskets.
After that I always spent more time verifying manifold fit, once bitten twice shy etc.
