These are the ones in the cars, in the trucks, iron blocks, but reality of weight difference according to brp is appx 85 lbs. Is this one a good deal, heck yeah, but you never know where bidding will end. The engines came in the cts-v, the gto's, ssr ect. The lq4 and lq9s came in the trucks/vans/suvs, and for a complete long block are running right around 1k to 1500 depending on mileage, while just a block is goign to run you about 3-400. I know parts from the lsx series will fit the lq4/lq9s for the most part, except the belt driven accesorries on the front have a different setup. Also with the truck motors, the intakes a little bit higher, so you've gotta watch that, besides that both are great motors