daft question time. what is the difference between a rev counter and a tachometer. i am after a rev counter but cant afford to pay the earth and rally designs have a well priced tachometer

No difference

1 and the same.

Tachometer is what we call it here in North America, and Rev Counter is generally what people call it in the UK. I could be wrong on the other hand. If so, it would be a first.