Engine - GM Performance Short Block Engines - Aluminum V8 Block

From GM Performance - This aluminum V8 bare block weighs 90 lbs. And is cast from prime ingot A-356 aluminum with heat treatment to T6 specification. Wall thicknesses have been increased for greater stress capabilities. The main bearing diameter is 2.45 inch. It's rigid deck surfaces are .620 inch. It has blind-tapped head bolt holes to improve head gasket sealing. The cylinder sleeves are semi-finished at 3.986 inch and will finish at 4.150 inch bore diameter. it has a 4-bolt main bearing cap on all five locations of 8620 steel which will clear standard oil pans. The rear main bearing is the 2-piece, pre-1986 design. These blocks are wet sump designed but can be converted to dry sump oiling by simply plugging the oil pump hole in its rear main bearing cap. Technical Note: Use cam bearing kit P/N 12370843.

From GM Performance - This block has the same dimensions and characteristics of the aluminum cylinder case (P/N 10185075) except that it has a 2.65 inch (400ci) diameter main bearing size and the bore is 4.120 inch. Use cam bearing kit P/N 12370843. This block is machined for a dry sump oiling system.