Created: September 22, 2006
Last time we chose a manifold based on flow volumes, and a carbie based on personal choice, but which combination is best on this engine? With the engine finished, it is time to look at a variety of carburettors, inlet manifolds and exhaust extractors, to fnd the most suitable combination. There are a lot of fgures, but they are necessary, so bear with me.
Created: July 24, 2006
Last time we started building a small-bore engine for maximum power. But there is no point having a good engine and putting the wrong head on it. I'm going to use the 12G202 head, as these are the best to modify for our purposes. They are a bit smaller than the 12G295 or 12G206 heads, which gives you a bit more metal to play with when grinding. As far as a standard head goes, you can't go past the 12G295 or 12G206.
Created: July 21, 2006
We all long for the power and torque available from a 1275cc engine, but with these becoming more expensive and harder to find, we’ll take a look at how to get some decent power from the smallbore engines. Graham Russell of Australia shares his ideas.
Created: July 24, 2003
There is no specific large-bore (1275cc-based) head casting number that will fit the 998 engine any easier than any other. They all have the same problems - generally requiring exhaust valve relief cut-outs machined into the block and re-alignment of the front water gallery transfer ports. However, I would avoid using heads with valves bigger than 35.7mm on the intake since these are too big for most 998 engines unless they are absolutely full-race spec where top end power at high rpm is all that is required.