To strengthen emissions controls, 1972-'76 TR6s had only a vacuum retard unit, while earlier cars had both advance and retard units. The later cars had up to 20 degrees retarded timing at the crank! With this modification you can enjoy the performance these cars should have. In about 15 minutes with the distributor out you can install this new unit, which replaces the original retard unit in distributors 41385 and 41558. If using original Zenith-Stromberg carburetors, you may require #365-315 vacuum port adaptor to access ported vacuum on top of rear carb by removing the existing plug (if your carb. doesn't already have the adaptor). You will need to plug the vacuum source used for the stock vacuum retard unit.
For non-smog inspected cars only!