Changing Frame Size and Stem Clamp Height

[Ed]

Hello,
I am changing frame size on my Giant NRS1...going from a small
16.5 to a medium 18. Giant specs show that the headtube on the medium
frame is about .4 inch longer.
I am wondering if the present fork will fit, because of steering
tube length. The Race Face stem now on the bike has about a 1.5 inch
clamp height. Catalogs and mfgrs don't seem to specify stem clamp
height. Headset is a Cane Creek (Zero Stack).
Can anyone recommend a good stem that has a clamp height around
the 1 inch area?
--Ed--