I've been having a lot of trouble with my rebuilt carb, 2bbl rochestor. Its on my 78 305 4 spd blazer, an dthis vehicle has the heavy duty emission option which means from the factory no cat, no canistor and definatly no egr. I just found out that if you put an egr carb on a non egr engine it will run to rich and cause sluggishness and other things because the jets are different. Well it does run rich and sluggish, and it just had a tune up a few weeks ago. The fix is to have the carb rejetted, but Ineed to know first how do I measure the juet size? And how do I relpace them? Any carb experts out there please help,cause this could be whats wrong. Thanks in advance - Steve.