Distributor Vacuum

[Mosesatm]

I recently saw a picture of a '68 289 with a dual port distributor in which the rear vacuum port was capped off.

That got me wondering.......since the rear port is for emissions and most emissions controls rob power is it safe to assume that capping the port would increase power or do the 2 ports need to work together? Would I be better off just replacing the double-port module with a single port unit?

Thanks for any insights.

 

[Mustanglvr]

Got any pics?

 

[J_Speegle]

I recently saw a picture of a '68 289 with a dual port distributor in which the rear vacuum port was capped off.

That got me wondering.......since the rear port is for emissions and most emissions controls rob power is it safe to assume that capping the port would increase power or do the 2 ports need to work together? Would I be better off just replacing the double-port module with a single port unit?



Thanks for any insights.

The whole IMCO system (as well as internal changes) was meant to reduce emissions. Just changing the hoses or the advance unit IMHO will do little especially if you are still routing the source through the ported vacuum switch, to change performance and doing so is illegal in many states.