Building Euro Spec SC engine - Lessons Learned

[lobster]

I hate being a guinea pig, but with no one posting any intel on a Euro build for the US(CA), I struck out on my own. Here's what I learned.
First off, this is a killer little motor. 3.0, 9.8:1, 964 cam, twin plug. Since Max Moritz pistons were not available at the time, I just left it stock displacement. But with 9.8:1 compression and living in CA, gas was definitely a concern. So, twin plug it. JB Racing CCW distributor with the curve set by Barry Hershon. This is a great distributor and Barry is someone who will make it work RIGHT. This is the second distributor I have had Barry work on. The first was my stock 78SC distributor with 280k and he rebuilt it like new. Props to Barry! The JB Racing is a very nice unit and uses what appears to be a Marelli cap so it's not too expensive. I think they make their own rotor. Not sure. The marriage of twin plug and CIS high compression is where things got tricky. I found out the position of the second plug is not entirely compatible with the CIS piston. Basically, it hits the top of the piston and mashes the electrode. I made a set of .100" spacers for under the plugs. What I don't know, but am not too concerned about is the piston growth at higher RPMs. This is essentially a stock motor, so high(7000+) RPM is not expected, so I don't really anticipate any further piston/plug clearance issues. The car now pulls SOOOO much better. Throttle response is much improved. People say that twin plugging provides no additional hp in these motors. That MAY be true, but the car is a different animal now, so if it isn't hp, then its torque. The difference between single plug on ~95RON and twin plug is ABSOLUTELY noticeable. Much stronger acceleration, and above 4k, its amazing. Clearly, there won't be any detonation issues now, so running 91 pump should be fine.
The other issues someone may be interested to know. Only 78-79 are the same as(FI wise) as Euro's. Fuel distributor, WUR etc, are all the same as. Big port heads.
Personally, I think the 78-79 are the best of the SC's. Easy to make into a Euro if you choose. The cost of the ignition is significant, but when your trying to build the most you can get out of a CA smog car, without going to a different motor, is just part of deal. I have bragging rights now too. Stock CIS 3.0 (SSI) that is probably good for `215. That would be my guess. I'll get on a chassis dyno here soon and report back.

[Reiver]

Very nice....a question about your WUR...I've an '83 930-10 Euro and my correct WUR is a 0438.140.089...is that the WUR that is in US 78-79 SC's?

BTW, I've been running mine in Az using 91 with no issues. I did put a Carrera oil cooler unit in place to reduce heat but I also run in 100+ degree weather.
I've used ACES 4 as a gas additive to raise the RON...have never had an issue.

The Euro 3.O's are sweet little motors.