The 250 carb could be smaller than the 292 carb but give it a try I bet it will be fine. Especially in Amman Jordan (wow) I bet carbs are hard to find over there?
I have run and clocked the earlier Rochester B carbs - the smaller 194cid/230cid version and the big 292cid version - swap em around on a 250 then a 292 engine and clock both - they run equally strong, dont seem to care which engine they are on. No rejetting needed. Of course the big carb will run better on a big 292, but a carb from a 250 will run fine, just have a little less top end.
