Thread: 350 flywheel

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I'm not an expert on this stuff, but I do know that the Gen I used two different flywheel diameters. Here's a paragraph from Novak conversions about them:

"Starting in 1962 there are two flywheels used -- 168 tooth and 153 tooth. The 168 tooth wheel used 10-1/2" or 11" clutches but the 153 tooth used only the 10-1/2" or smaller clutch. Also starting in 1962 the starters are mounted on the block. Starters, drives and solenoids are essentially the same but there are two end castings used to correctly position the starter relative to the flywheel size. 1962 and newer V8's have three starter bolt holes in the block. Only two are used to mount the starter. Starter end castings vary with flywheel diameter. The starter casting with bolts in line (at right angle to the engine certerline) is for 153 tooth Flywheel. The starter casting with bolts offset from a right angle to the crank is for the 168 tooth flywheel. Also starting in 1962 the bellhousings are die cast aluminum -- the 4-11/16" bore was most common. There were some 1962-1971 aluminum bellhousings that were used with light duty transmission -- these had a 4-3/16" bore and were used with 153 tooth Flywheels. The 168 tooth flywheel will not fit in these bellhousings."

Then there's a passage about the later 'wheels:

"In 1986 a crankshaft and flywheel change was made. 1986 and newer Chevy engines will not accept older flywheels due to the different crank flange and bolt pattern. Older bellhousings, however, will work on 1986 and newer engines."

Here's a paragraph from Advance Adapters:

"The flywheel can either be 153 tooth, measuring 12-3/4² in diameter, or 168 tooth, measuring 14² in diameter. The 1985 & earlier flywheels are not interchangeable with the 1986 & later flywheels, due to a change on the flywheel crank bolt pattern and balancing. If you are using a stock GM bellhousing, make sure you have proper clearance for the flywheel. For the proper starter, GM used two different bolt patterns on the bottom of the block. The straight bolt pattern is normally used with the 153T flywheel, and the offset or staggered starter bolt pattern is normally used with the 168T flywheel. Many Chevy blocks today offer both starter bolt patterns on the block."