Blackcircles.com is the cheapest, they will supply to you, or fit at a garage near you

I have amps, oil temp, oil pressure, water temp, may have a clock to fit as well, all out of 1971, ranger41

The engine is idling to fast, suggest first change the temp sender about £12, this sends a signal to the computer to inform it of engine temp.this then controls mixture strength. Secondly, throttle position needs to be checked with engine off, potentiometer on plenum chamber needs to be checked...