1515 Old US Hwy 31 N. 1999 Cummins ISB Diesel Engine. Stock # R 1790. Our Engines come with a. (Only Applies To Good Running Engines, Excludes Cores/Take Outs). We remove Valve Covers and Oil Pans to inspect the Internal parts to ensure quality. World Wide Diesel Pays for your core to come back. Easy Simple Core Criteria (Complete flywheel to fan hub, Turns 360, and no holes in the block). For More Information Contact. Worldwide Diesel original – YouTube.