If you are building this body from scratch, you need a neck pocket positioned relative to the bridge in the same place as you would find on a Strat. That way, the neck would do the converting, as
@Spud has suggested. If you have a template for a Strat body you could use that to determine the placements.
However, if you need to work out where that is and you have the neck, you need to measure for a 24 3/4" scale to work out where to place the neck pocket and bridge.
If you go to
https://www.stewmac.com/fret-calculator/ and put in a scale length of 24.750 to calculate fret positions, the tool will then provide at the bottom of the page where exactly you need to place the bridge for different types of bridges.