10 speed to 8 speed conversion

GiantMike Posts: 3,139
edited August 2009 in Workshop
Please bear with me on this. I am building an 8 speed X-cross bike and I've been offered a 10 speed rear mech. Presumably the amount it moved is controlled by my 8 speed shifters but the 8 speed chain will be too fat for the jockey wheels. Correct?

Therefore, can I use the bolts and jockey wheels off a scrap 8 speed rear mech to turn it into an 8 speed?