289: These engines had a 2.87" crank stroke and used the same main and rod journal size as the 260 or small block 302. The 289 has the oil filler tube in the front passenger side corner. The VIN stamp was moved from the front of the block just above the oil filter. The 289 used a long or “big” water pump. The 289 used a 3/8” frost plug behind the distributor. The small journal main bearing diameter was 2.204”. The piston ring size was .043". The 289 block is longer than the 302 by .2”.
302: These engines had a VIN number above the oil filter on the front of the block and use the same size pistons and crank stroke as the 289. The difference is the 302 has a cylinder wall approximately .1” thicker than the 289 for a total bore size of 4.00”. The 302 used a longer or “big” water pump. The 302 used a 3/8” frost plug behind the distributor. The small journal 302 engine main bearing diameter was 2.204”. The piston ring size was .043”.
Late Model 302, 5.0 and 351W: These engine blocks used a one piece rear main seal, larger pan rail and pan rail bolts, and a shorter or standard water pump. The late model blocks have the VIN number just below the cylinder heads on the front of the engine. The engine displacement can be found cast on the front passenger side of the block (302 or 5.0 or 351W). For these blocks the cam bearing journals were increased in size to 1.849” OD. The rear main cap seal surface and the 5 main caps were also increased to 2.496” OD.
