Porsche 356 Carrera 4-cam
This is a study in the development of a Porsche 4-cam engine that we tested over a period of time. The engine grew from the baseline 1600-cc displacement to 1750-cc by increasing the bore size. The larger engine had hotter camshafts, ported heads, larger racing Weber carbs and a custom header. We designed and built the header based on our engine simulation program. The result of all this work was an obvious increase of top-end power at the expense of a compromised power curve in the lower RPM range. While the 1600 engine could be driven on the street, the 1750 version was a race only proposition. We didn't take the 1750 engine over 7,200-rpm at the request of the owner, so it may have made slightly more power than it did during our dyno testing.
Click on thumbnails for larger images.
1750-cc horsepower after: 161 @7,200 Torque after: 126 lb/ft @6,300
1600-cc horsepower before: 136 @7,100Torque after: 110.5 lb/ft @6,000
Type: Porsche 4-cam Carrera, 1750-cc
Compression Ratio: 10:1
Cylinder heads: Ported 4-cam
Camshafts: Carrera racing
Induction: Twin Weber 46 IDM
Exhaust: Carobu custom 4-1
Ignition: Dual Bosch distributors/coils