Gilmer belts

Hey guys, is anyone a master with Gilmer belts? I've got a friend with a Gilmer kit on a 12a rotary to go around crank/water pump/alternator. But he's planning to go electric water pump so the belt needs to be shorter. The only reason for the Gilmer is for the noise so the fellas not too bothered if it gets taken off and changed back to a vee belt. I've had a quick look with no luck so just wondering if anyone knows if there's a range of sizes to choose from or only size's for certain setups. If not back to standard it goes.

Cheers to anyone that might be able to point the right direction.

There are numerous guides on-line on how to size a belt, if you use one of those you should find something in the length range you need, with the correct width and pitch.

You will probably find something on the current belt like 300L which will identify what he has, but there's a breakdown guide here that goes into more detail - https://ww2.gates.com/IF/facts/documents/Gf000191.pdf