Connections for '78 - Earlier years are similar, but didn't have all the same components. Refer to the parts listing which has the Porsche and Bosch part numbers for the particular year model. For instance, if the year model is a '75, the system doesn't have a thermovalve, (number 4 above), and there won't be one listed in the parts list. Just replace the #4 above with a continuous hose length.

Vacuum connections for the '80 - '83 CIS. Notice the configuration of the deceleration valve (13) has changed, and the frequency valve (8) has been added, which is controlled by the Lambda sensor electronics box.