internally the C6 should be the same (the winnibego might have the heavier clutch packs in it but might not too) the engines should be the same, expecially if the casting number on the side of the spare block is D9TE, should be right above the starter, and that will be the same casting number on the block in the motorhome. the heads on the 79 should be D3VE and the heads on the motorhome engine might be E5 or something like that but they are totally interchangable.