Yes but an RS1600i lump is exactly the same as an XR3 lump. The only special bit is the head/cam etc. Without that you might as well have the bottom end from a 1.6GL.

The RS head already has larger ports and valves so exchaning a genuine head with the solid lifters, higher ratio rockers etc for a worked over XR3i head is a very curious move.

Quite often when someone buys a RS1600i lump it ultimately turns out to be an XR3i lump with the motorsport rocker cover on.[/i]