vacuum line routing after smog removal?

[Redtail]

I just finished removing all the smog crap from my '73, something a PO started around a decade ago. I'm wondering if there is any insight on how I should re-route my vacuum lines?

Most importantly, any ideas about where I should hook the vacuum advance from the dizzy? Would the manifold pull too much vacuum?

thanks,

-Zack

[Arizona02]

above the throttle plate primary side, vacuum will be near zero at idle and will increase with rpm w/ increase throttle opening.

[johnhup]

Hhaha.. you're on this board too Zack?

Yes, keep the vacuum advance, especially with your 32/36 Weber.

[mikem]

Carb or manifold?

[Redtail]

Hey thanks guys - I'll try the port on the carb. Should I just plug all the other vacuum lines? I don't think there is anything I need them for other than the advance.

Hey John - How's the silver 02? That's good news about the crane - def on my list for the future. here's a picture just for fun

[Redtail]

My vac advance line is currently connected to the manifold, but i think it pulls too much vacuum there.

[Zenon]

I just finished removing all the smog crap from my '73, something a PO started around a decade ago. I'm wondering if there is any insight on how I should re-route my vacuum lines?

Most importantly, any ideas about where I should hook the vacuum advance from the dizzy? Would the manifold pull too much vacuum?

thanks,

-Zack

Hey fellow Z-man,

Carby '73s came with a "vacuum retard" distributor. Assuming yours still has one, then I recommend that you disconnected the dizzy vacuum unit entirely and just cap all the vacuum ports on the manifold and carb. The dizzy then becomes a "mechanical" unit, using only it's centrifugal advance mech. Fear not - the retard function was an emissions-related thing and if the Solex DIDTA carb has been turfed then there is no longer a proper way to connect it, anyway.

If the vac line was connected before, then you may notice a need to re-adjust the idle speed/mixture and possibly also the timing itself after you disconnect it.

A more ideal setup for a carbed street '02 - assuming the motor is still the original 8.3:1 CR - is to use a "vacuum advance" distributor as found on the non-'73/74 years. You will gain some MPG and part-throttle response but full power operation will be unaffected.

regards,

Zenon

[johnhup]

How can you tell if you have a vacuum advance or not? I just rebuilt my '73 motor and put back the standard distributor. Any part number? Disconnect the vacuum and drive it?

[DukeRimmer]

ported vacuum at carb base. Ported means little or no vacuum at idle, sudden full vacuum off idle.

[Zenon]

How can you tell if you have a vacuum advance or not? I just rebuilt my '73 motor and put back the standard distributor. Any part number? Disconnect the vacuum and drive it?

Look at the points plate - on a vaccuum retard dizzy, the plate gets pulled clockwise when vacuum is applied, on a vac advance dizzy, it gets pulled counterclockwise. The link gets pulled into the vac module when vacuum is applied to it.

I don't agree with Duke on getting rid of the vac retard dizzy 'just because... It is not at all bad to use it without the vacuum connected and is still better on a stock carby motor than the non-vacuum tii dizzy that is usually (and mistakenly) considered an upgrade. If it is worn, then sure, you may as well replace it with a vac advance dizzy but otherwise save your shekels for something giving more bang.

regards,

Zenon