Engine - GM Performance Short Block Engines - 350ci Bare Block

From GM Performance - This engine block is used in 1986-99 Gen I heavy-duty applications. It has 4.00 inch diameter cylinder bores and four-bolt main bearing caps. This block is machined for a one-piece rear crankshaft seal. (Does not included rear seal or adaptor.) These blocks weight 197 lbs. Technical Notes: Cylinder wall thickness is the same as current production engines. The lifter valley is machined for hydraulic roller and flat tappets. Crankshafts with two-piece seals can be installed with adapter 10051118. (Block casting 10243880 or 14093638).

From GM Performance - This350ci iron bare block is used on the 1973-85 GM Goodwrench 350 engine and has the early-style 2-piece rear main seal. Its main bearing caps are the straight type four-bolt design. The block has a standard 4.00 inch cylinder bore. Technical Note: Can be used for 302, 327 and 350 engines. (does not include oil galley plugs or dowel pins.)