Just a note about descussions on here and other forums about fitting xr2i cvh heads onto rs blocks, people think that u can just one onto an rs block.
The head its self is the same but the valves and valve seats are differnent, every thing else is the same so beware.

 

The heads are identical as are the cam, valves etc. The only difference is with the cam pulley which has a little more retard than the XR item. Only the S1 Escort RS Turbo has different valve seats.

 

I thought the exhaust valves are different on EFI TURBO/NON TURBO!?!? Same size but made out of different metals

 

My man says there are differnt valves listed, must have something in the matal as the valve seats

 

Even the injectors are the same between the XR2i and RS Turbo. To the best of my knowledge the only difference is with the S1 Escort RS Turbo which had sodium valve seats in the head whilst the XR3i didn't.

To the best of my knowledge

 

I heard different

Read puma race engine page about tuning the cvh

The difference Is more material to work with when fitting bigger valves and porting ect

So he says it's the best head to modify for big valves