I have two flywheels for manual transmissions. They are both Gm and 153 tooth. One is for a 2 piece seal and the other is for a 1 piece seal. But the one that is for the one piece seal is like a good quarter inch thicker when they are both laying flat. Will it still work and why are they different thickness?? Thanks Kevin

Anyone?

ttt

PLEASE!!!!!!!

Hm, it is My understanding that the Differance between the TWo Flywheels (1 peice and 2 peice rear main ) is the 163 and 153 teeth differance, But I could very well be wrong.

Other than that, No idea (

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The 2 piece rear seal flywheel is for use on 1985 and prior blocks because they are internally balanced. For 1986 and newer engines the thicker flywheel is needed because they are externally balanced and need the extra wieght.

Well it is the flywheel for the one piece seal that is thicker. I just wanted to know if it will work. Does the thickness matter. I think it may have came off of a 283? But I am not sure. Thanks Kevin

You'll find the bolt pattern for the 1 pc rear seal flywheel/crank is smaller than that of the 2 pc rear seal crank/flywheels.

Yeah, I don't believe that they will even bolt-up... Cannot swap anyway because of balance issues...

But i should be able to use the thicker flywheel on my 84 motor then. Regarless of thickness. I dont need the flywheel for the 2 piece seal. It just happens that i have both and am wandering why the one for the one piece seal is alot thicker??

No, you cannot use the one piece seal if you are building an 84 motor. Blocks prior to approx 86-88 year models were two piece rear seals. The bolt circle pattern on the crank and flywheel of the one piece seal design is smaller in diamter than the 2 piece crank's bolt circle. They won't interchange or bolt up. Thanks to wonderful GM, the 87-88 was suppossed to be the year change-over to the one piece rear seal design, but some earlier 86-87 blocks got it, some 88 blocks didn't, so watch the change-over year models.

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KevinP92Z
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God am I stupid! I ment to say can i use to flywheel for the 2 piece seal on the 84 crank!! It is 153 teeth and the only thing i see different from the other one is that it is thicker. Sorry for all this confusion..... Kevin

The crank flange is different in several ways.

It is sufficient to say that if you bolt a one-piece flywheel onto a one-piece crank, the clutch surface comes out in the same plane as a 2-piece assembly. They are totally interchangeable as an assembly regardless of the thickness of the individual parts.

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"So many Mustangs, so little time..."

OK That is what I wanted to hear! Thanks Kevin