cis interchangeability
 

Hi, I'm usually a lurker around here and answer most of my own questions using the "search" option ... but after searching through 180-odd posts containing"cis" I can't find a clear answer.

So I've decided to ask the wealth of knowledge here for help in answering my question.
Can the cis injection system from a 1976 911S be used on a 3.0 or even a 3.2 without any adverse effects? or am I forced to purchase complete engines.

Thanks in advance for any help.

I can give you a quick answer and can follow it up with more detail if you need it:

No, but I quess you would have to say what you really mean by "adverse".

The throttle body is a size too small, and the airflow sensor plate and venturi are not optomized for a 3.0 liter displacement. The fuel distributor is also different, and I can't say what the spec differences are, but again, not optimum. The fuel pump is too small.

A 3.0 liter engine will run with a 2.7 liter injection system, but not well enough to extract the horsepower from the engine it was designed for. To back this opinion up, a 911 owner that posts on the 911 Rennlist email list just went through this several months ago, and reported after installing the proper 3.0 injection components, could tell a noticeable difference.