Why does the curb idle speed increase...

[rnch]

when I install the air cleaner lid on my '65 Galaxie, 352 4BBL autolite carbed engine?

 

[wbedwards]

you need to adjust the idle with it on, or you have a dirty/restrictive air filter

 

[Alaska Jim]

or there is the possibility that you have a vac. leak or are just lean on the idle mixture