What compression Ratio?

[jules325i]

Im building my 2002 m10 soon (street car).
Parts i have so far

HD Rockers
IE 292 Camshaft
HD single valve springs
Rocker locks
Twin 45 DCOE Webber's
Full exhaust including Headers
Ordering Forged pistons from IE (Ross Racing)

Now what is a compression ratio that i can use on pump fuel being 98 octane. (I'm thinking 10:5.1)

[visionaut]

I believe you Aussies measure octane different that us Yanks. For the typical 'hi-test' we get here, 9.5 would be a better option than 10.5 - to avoid pinging at best tune.

Tom