And by the same size I meant that Camry's and Runners both have 295mm diameter rotors
Why do a rear disc conversion at all vs the Tundra upgrade for the front?
Here is one example of the kit. Maybe just needs a new adapter to work on a 3rd gen 4runner...
https://www.allprooffroad.com/8489brakeupgrades/33
Before you use this junk, call and ask them to sell you just pads, they won't. I have first hand experience with this kit. Looks nice, and actually works(once you work out getting it installed), but I wouldn't use it again, ever. Kit is a 4 letter word invented by marketing bozos.