Engine Decoding
 

I have a 79 911SC. Ibought the car as a rolling chassis project. After a couple of years I purchased an engine for it. I have had installed and was driving it last summer. I decided to go to carbs on it instead of the CIS injection that started giving me headaches. Currently during the carb install, I started research to see what size I should make the intakes and started runing engine code numbers. The engine coder says it's a 1980, and a U.S. spec engine. The wierd thing is, it is the large port CIS and the intake ports are 39mm instead of the correct 34mm. I guess there coluld have been some swapping going on, or work done, But the intakes seemed to be untouched. Has anyone ever ran into a similar issue when decoding their cars.

bump

I'm no expert, but I think the 1979 and 1980 cars came with larger CIS intake runners. These should be a good upgrade for someone that is going to electronic fuel injection.

The intakes got bigger on later models so you've probably got what the car came with.

I see I understood it to be that 78 79 models had the large intake runners, and 80 81 82 had the small intake runners. Thats what I thought. My book stats that my intake ports should be 34mm and they are 39mm. Maybe I need a new book. LOL

Take a look at the engine code.....it's down by the oil sender near the bottom pulley. Engine serial number AND the 930/XX number. It's a little fainter, but it's there.

I got the engine code, 930/07. It says small intake ports, U.S. spec, but it has large intake ports, and large port F.I.. I don't know. I guess it doesn't matter much as long as I match port the intakes right?

930/07 is from MY80, US SC, small ports(34/35), 9.3cr, 180hp@5500, 175lbft@4200

'80 was the first yr for the small port SC 3.0s