2.5td to a 300 conversion temp sender

Hi guys, i know this has been covered quite a few times, but I'm finding so many answers and I'm totally confused, my landrover used to have a 2.5td engine in it years ago, ( G reg) but had a dodgey 300 conversion done to it now during my re chassis I'm changing it put a newer 300tsi engine from a disco in,

What temp sender can i use to get the gauge reading right? Is it possible or do i need to just get a new gauge and use it seperatly?

Thanks a lot

Eds