Does the CAI mechanical water temperature guage come with different size sender tubes, as I require the smaller diameter tube to fit my cylinder head.
No, the CAI Smiths mechanical water temperature gauges always come with the same tube/sender/capillary arrangement.
The bulb is fitted with a 3/8 BSP sleeve nut and comes with an adaptor to 5/8" UNF male. This is the thread in the head of Austin/Morris A and B series engines, Rover V8 and many engines of that era.
There is an alternative adaptor with a 3/8 BSP male/male thread that is often used in the header tanks of race cars. The diameter of the bulb is about 3/8 inch.
11th August 2015