911SC 9.8 CR experience in CA

[snafua]

I am rebuilding a 1979 3.0L engine in California. The Cylinders are Alusil, and if my research is right, it has a 8.5 CR. So assuming I should replace them with Nikasil Cylinders, I thought why not go to the Mahle 9.8 CR euro P/C's on this site. So a few questions.

Does anyone have any experience running CIS with a 9.8 : 1 compression ratio in California and pass smog?

Reading Wayne's book, I also see he suggests going to a 964 cam. Why? And if I don't, am I just giving up power, or something worse?

Any other gotcha's when changing the compression ratio?

Any insight or experiences are appreciated.

[Walt Fricke]

My understanding is that you won't be able to find the Euro 9.8 Ps and Cs. Which makes this a moot point.

These motors run fine with the stock cams, which you already have. The 964 is a hot rod cam, so to speak, for these motors. So nothing worse.

[Henry Schmidt]

Euro Ps& Cs are still available plus there are ways to transplant the 95 mm 32 Ps&Cs into a 3.0 yielding huge compression.
That said. the combination of hot days and poor octane quality makes running anything higher than 9.5:1 a genuine gamble.
It's not uncommon to find damaged pistons (from detonation) in a 80 to 83 SC which purports to have 9.3:1

[Walt Fricke]

Henry - guys racing in PCA stock classes are telling me they can't find the Mahle Euro 9.8s. They can't use aftermarket or adapted 3.2s because of stock class rules. The Cs aren't a problem, but getting the Ps seems to be.

One racer found that his Euro pistons were the 9.3s from 1980, when the Euros ran that. He's naturally looking for the extra squeeze to which his class rules entitle him.

Where might one look?

[1979911sc]

There was a set of new 9.8:1 mahles on ebay the other day and I believe rothsport makes 9.8:1 forged cis pistons also on ebay.

[Flat6Heaven]

Well, I might be interested in selling my 9.8:1 pistons and cylinders. 1982 930-10 ROW engine with 180 000 kilometers (under 120 K miles).

I will also consider selling the entire "204 hp" CIS injection with metal injection lines, as well as the distributor.

I want to build a hot 3.0 or short-stroke 3.2 with ITB EFI and am debating whether to sell or mothball the stock parts. Feel free to PM me for pictures / video if interested.

Regards,
Ben.

[camgrinder]

Either profile (SC or 964) will pass emission tests. The 964 will be better for California pump fuel with 9.8-1 compression.