SSI heat exchangers are back! For years American owners of classic 911s have worshipped at two stainless steel altars called SSI heat exchangers. They are basically a better-than-original replica of the pre-1974 heat exchangers used by Porsche until 1975. That’s great if you have a US model...

Tuning the 911 CIS engine for cheap horsepower Porsche 911s produced 1973 to 1984 are fed by a Bosch K-Jetronic fuel injection system also known as CIS for Continuous Injection System. It was a huge leap forward compared to the old mechanical injection. And in a...