Vacuum advance & carburation

[blue bus]

I have a 1970 911t motor. I have tossed the mechanical advance marelli for a vacuum advance bosch.
Here is my problem. there is only one vacuum line on each bank of carbs (zenith 40 tin) i only get vacuum on start when #2 and # 4 cylinders are firing.
How do i get vacuum from all 6 cylinders. I have heard of people drilling and tapping two more lines in each bank but that sounds a little dicey.
Any suggestions?

[RoninLB]

single line 911 Bosch dizzys are vacuum retards

I run straight mechanical advance

vacuum ports on carb intake manifold are for power brakes

[blue bus]

Thanks for the input.
Anyone else?

[James Brown]

you don't need vacuum on the Bosh but you can disable the aux. enrichment system, if you haven't already done that, and put vacuum hose on all the ports, feed them to a manifold then out to the distributor. that should give you good constant vacuum

[psalt]

The Bosch has a mechanical advance. Vacuum advance or retard is in addition to the mechanical advance, advance for economy, retard for HC emissions. Bosch distributors with vacuum advance use ported vacuum (no vacuum at idle), the retard uses manifold vacuum (full vacuum at idle). What are you trying to accomplish ?

[blue bus]

It is only an issue with cold starts.
That is what i am trying to achieve, better start up. I can live with it the way it is but i am bit of a perfectionist and it drives me nuts knowing that it could be better than it is.