Just got off the phone this morning with GM concerning new GM performance engines. They are in fact going to make available in July a high performance 383. I'm so excited! The price is about $3,800 so that might be a deterrent for some. If you'd like to take a look at the specs here is the GM performance catalog online Part number 12497317. https://www.spoperformanceparts.com/store/catalog/templates/MainCatList.jhtml?CATID=2 1990 GMC Jimmy 350/TH700R4/NP241/10 bolts, 4" skyjacker lift, 35x12.50R15 BFG All Terrains on 15x10 AR Baja's, Flowmasters.