The 302-cubic-inch, small-block Chevy (SBC) was a meagre engine produced from 1967 to 1969 and available by oneself in Camaro Z28s. Allying all first-generation SBCs, it has many bourgeois, interchangeable components. The 3.00-inch-stroke crankshaft was shared with the 283-cubic-inch engine and the cam and heads were borrowed from the Corvette 327-cubic-inch engine. The alike engine block was used for three SBC V-8 displacements in the Camaro -- 302, 327 and 350 cubic inches. All share the same piston diameter of 4.00 inches, so creating a 302-cubic-inch engine from a 350 block is possible.
Instructions
Disassembly, Machining and Parts Sourcing
1. Disassemble the 350 core engine and take it to an engine machine shop for cleaning and inspection. Have the critical surfaces (main bearing journals, cylinder bores and block deck, etc.) machined to recommended tolerances. If the cylinder bores need to be machined/bored to a larger diameter, make a note of the new diameter.
2. Order or locate/purchase the necessary rotating components (crankshaft, pistons and rods) to "de-stroke" the 350 engine to 302 cubic inches. The 302 engine uses a 3.00-inch-stroke crank as opposed to the 350's 3.48-inch stroke. Note that the 1967 350, 327 and 302 blocks used crankshafts with smaller rod and main bearing journals, while 1968 and later blocks had slightly larger journals. Be certain to get the proper specifications from the machinist.
3. Have the cylinder heads cleaned and reconditioned while the engine is disassembled. The engine machinist will likely have the expertise and equipment to accomplish this task. While all first generation SBCs heads are interchangeable, late-model GM SBC heads (such as Vortec and "L98" heads) have as much -- or more -- performance potential than even period-correct, late-1960s performance heads.
Reassembly
5. Clean and final-prep the engine components and test-assemble the short block (block, crank, rods and pistons).Aftermarket performance heads are also an option.4. Order a camshaft and lifters (a complete kit is optional) that are suitable to the displacement of the engine and the intended use of the vehicle it will be operated in.
Use the tolerances for clearances and torque values for fasteners recommended in the assembly manual. If there are any clearance or tolerance issues, address them now.
6. Install the new camshaft and lifters.
7. Install the cylinder heads and remaining valve train components, and then install the intake manifold and carburetor.
8. Swap reusable parts from the donor engine, such as the water pump, distributor and starter, to the new engine.
9. Install the engine and test-run in accordance with the cam manufacturer's break-in instructions.
