Back in the 1960s & 1970s if you wanted to uprate the power of your Lotus there was only one place to go, Ian Walker Racing (IWR). The attached image includes a written quotation from Ian Walker Racing and the Lotus Twin Cam sales leaflet for a reconditioned Stage 1 big valve engine for £255, a meager sum by todays standards however pricey back in the day. IWR used to offer six stages of engine tune for the car at prices ranging from £40 to over £400, whilst braking, handling and transmission changes could be ignored, at least until the fourth stage of tune was applied. A customer could expect anything from a 20 to 50% increase in brake horse-power.

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