Shop Solutions General Motors / Chevy 191/3.1L Advertisement ByEngine Builder on Feb 1, 2000 When this engine was used in the plastic mini-vans, it came with cast iron heads and the old, original, carbureted, non-H.O. cam. This cam was used because the reduced lift and overlap gave it a smoother idle. ItAdvertisement Advertisement In this article: Shop Solutions: Shop Solutions January 2021 Shop Solutions: Shop Solutions – December 2020 Shop Solutions: Shop Solutions November 2020 Shop Solutions: Shop Solutions – October 2020 Advertisement VIDEOS Watch Engine Builder's latest discussions and explanations. SHOP Shop the latest Engine Builder merchandise. SUBSCRIBE Stay up to date by signing up for the Engine Builder newsletter.