Additional core charge of 3000.00 not included. Caterpillar 3126 Complete Drop-In Engine 64F8D300SB. Serial Number 8YL, 7AS, CKM, 9SZ. 3126, 3-Valve, 230-up HP, GMC Bus. Ordering Instructions: Provide vehicle/equipment year, make, model Engine Model, year, Arrangement number, and Serial number.. Call us toll-free 1-800-282-9319 for ordering assistance and complete warranty information.