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.
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.
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.