Thanks guys.
I wasn't aware that the ring gaps would be supplied with the rings.
As for piston running clearances (piston to bore); i will be checking that the parts i'm using aren't far from stock data which i'm sure i found somewhere yesterday.
dsm2002 - where did you get the data from. I hunted around for data like that most of yesterday afternoon with no luck. I mainly found lots and lots of dead links to Bentley manuals. The only section i want is the M42 data.
Engine is going to be used for track and sprint and a thrash around the countryside every so often.