TSP 376 CID Sleeved Gen 5 LT1/LT4 Short-Block, Stock StrokeAll Texas Speed & Performance resleeved short blocks use a NEW resleeved Gen 5 aluminum block with Darton dry sleeves! All resleeved blocks are fully machined and assembled at our facility, and we use state of the art Darton dry sleeves that have a much higher tensile strength than the standard GM sleeves. They are also much thicker than the sleeves used in GM blocks. We do not recommend running larger than a 4. 125" bore size if you are using any