which vac port?

[wheelman21]

I have a 340 with a 509, 242@50 cam and M1 intake. The instructions for the carb say the front port is for vaccum advance and the rear is for diagnostics. Don at FBO says use rear port for vac advance. Which one do I go with?

 

[Burntorange70]

The one with out vaccum at idle.

 

[rumblefish360]

IDK , WTF Don is talking about.

Which carb do you have? This would be a BIG clue!!!!!!!!

Good answer Burnt!

 

[wheelman21]

Sorry I left that out. It is a 650 mighty demon. The front port is ported, the rear is manifold I guess.

 

[Snake]

You want ported.......

 

[wheelman21]

That's what I thought too!