2nd gen 97 differance from 98

I am looking into collecting parts to repair my 97 3500. Before I spend money on parts I would hope to learn the differance between the 97 and 98 trucks.
Are the frames the same? Are the engines the same? Are the electrical systems the same? Are the front body and substructure parts the same?
Are the intercooler, trans cooler, AC condenser the same?

Thanks for the help,