I have a 1970 E-type Series II DHC.

In replacing distributor cap, rotor, points & condenser, I noticed that there is no vacuum line connected to the vacuum unit of the distributor. The previous owner had "sleeved" the carb, bypassing the secondary. I guess that is a common modification for performance. Could it have any relevance to the missing vacuum line connection? Where is the connection to the vacuum unit supposed to come from? I see no open line or even a connector on the manifold.

 

Previous owner did you a large favor...If you don't need a "concours" car, then leave the setup alone....The vacuum connection is on the intake manifold, on the end closest to the firewall...Hopefully it is plugged or capped....
Your timing is now by mechanical advance, and should be set around 10 degrees at idle.....(this varies by engine)....
The '70 is the only 4.2 , that had a vacuum "retard", instead of advance...This was to meet the new smog regulations...It ruined performance....Changing back to retard setup will be expensive, if the diaphram in the dizzy is bad (which it probably is), or a different distributor has been installed with no vacuum advance....
My '70's performance improved dramatically, when I removed the retard(ed) setup.
Edward

 

 

There is a chance your car is titled as a 70 but a late 69. If so it would have neither an advance or retard as mentioned.