I came across a 1991 350 that runs great and has 86,000 original miles. It's the original engine in a van. How can I get it to run in my 1981 Z28? I've heard that I may have to change the TBI over to a carb and probably switch the distributor. Is there anything else? Also, Is this a roller-cammed engine?  

Just swap the intake, carb, distributor, and front accessory brackets from your Z/28s current motor over to the van 350. Everything will bolt right up, and your problem is solved.

No, that '91 motor is not roller cam equipped. GM didn't start putting roller cams in the trucks until '96. But, that block does have the taller lifter bores of factory roller blocks, so installing a roller cam is no problem.  

Thanks for the info. I should have it up and running soon. I researched the 1991 van engine and discovered that the power levels (190hp & 300lb/ft) are almost identical to the original Z28 engine. Shows how far we've come.