C/R ?s and converting 3.0 to euro specs?s

[Mookster]

I didn't get alot of responses on the rebuild forum, I hope you all can help me understand.

I have Wayne's rebuild book and I am looking at page 113 on Wayne's engine picks. I am just trying to understand some of the fundamentals of gaining hp/torque without breaking the bank when the time comes time to rebuild/modify the motor. I understand I could make a 3.2 short stroke to get some more ponies but the $3000 outlay for carbs defeats the purpose of affordable hp.

I have a 1983SC with a 3.0L USA engine with 9.3:1 CR based on the spec book. The euro version of the same motor has a CR of 9.8:1

1. What do the CR ratio numbers mean? 9:3.1 and 9:8:1

2. Hypothetically, if I were to rebuild my motor with new euro P&Cs what additional modifications to the motor, ignition, and fuel system would be needed? In this hypothetical can I use my current CIS fuel system, cams heads, valves effectively.

The reason I ask these questions is I see some of the parts cost differ for small dollar amounts. If you are going to drop this kind of coin on some of these "bolt on parts" the logic seems, at least on the surface, to upgrade to more displacement or higher C/R.

My goal is to make a reliable inspired motor for daily use.

All answeres and explainations are greatly appreciated in advance.

[dd74]

Mookster: the 3.2 short stroke is a very good upgrade, recognized by the Porsche factory per Bruce Anderson's book.

As for duplicating a Euro '83 SC, you're going to need quite a few bits and pieces that are not on the US SC motor from the same year. Namely heads, larger 39mm intake, the Euro fuel distributor and the higher compression of the 9.8:1 pistons.

Sometimes these parts crop up on the Classifieds board, but in some regards there are several authorities in the Porsche world who believe the difference between a Euro '83 SC motor and the U.S. version is minimal at most. If a difference is noticeable, it is at the very top end of either motor's capabilities.

The 3.2 short stroke won't yield an enormous amount of horsepower - unless you change your induction system and cam - but it should provide more torque.

[Mookster]

Thank you for your responses.