The casting numbers are to the right of the dip stick for checking the oil 6 or 7 numbers. Also quick check is the height of the side 4 inches high 250 or smaller, 6 inches high 292. Hope this helps.
Larry
68 C20 327/465 daily driver 4:56 och!
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65 C10 ? /powerglide Custom Cab AC,PB,PS,4xflasher
