Going HEI was the best thing I ever did on mine. Did it add performance? No. Did it help make it run better? TONS.
http://www.ebay.com/itm/CHEVY-INLINE-6-CYL-230-250-292-HEI-DISTRIBUTOR-6523-BK-BLACK-/331659454921?hash=item4d3871a9c9:g:SWEAAOSwiLdV~X-6&vxp=mtr
That's the one I bought. You'll also need new plug wires. Old ones will work but not properly.
