projectheaven

Do you guys know what parts are interchangeable between the 350 and 455?

64Rocket

oil pan, oil pump,oil pump drive, water pump, front cover, timming chain & gears, valve covers, distributor, rocker arms, water neck, acc. brackets, pulleys, motor mounts, the BB heads will fit small block, but not a good idea, unless you do major work.

Gene

geckonz08

gene, good answer
mike

joe_padavano

Cam and lifters (allowing for 39 deg vs. 45 deg blocks and 0.842 vs 0.921 lifters). Also, oil pans will physically interchange, though the SBO pan is slightly different from the BBO pan. And finally, flexplate/flywheel within the 64-67 and 68-90 families.

projectheaven

So some of the internal parts won't interchange?

1971olds350

maybe some bolts?

joe_padavano

None of the reciprocating parts interchange. The BBO uses larger main and rod bearing diameters than the small block (exception: the diesels used BBO sized bearings and a BBO crank can be stuffed into the diesel block with some machine work). Rods are different due to the bearing size. Some pistons can be interchanged. For example, one popular swap is to use 350 Olds pistons (4.057" bore) in an early 400 BBO (4.000" bore) since the early 400 pistons are hard to come by. The compression height is the same for the 64-67 BBO and all SBOs. The 68-76 BBO uses a different compression height and different rod length.

Of course, pushrods are different due to the taller deck height on the BBO. Timing gears and chain are the same (as noted previously), as is the oil pump. And valves can be swapped (with the appropriate machine work), since the factory put BBO valves in the W-31 heads.

And yes, with enough machine work, you can swap all kinds of parts.