T56 Flywheel Explanation

[MinesGT]

I am currently installing a 1994 LT1 T56 box onto my 1988 SBC350.

I am ready to connect the box prior to install (will be using the hydraulic clutch).

I have read the advice on this forum about using the flywheel from the LT1 engine? (which i do not have at present!). What i would like to know is why this flywheel needs to be used? Just trying to understand, as over here in the UK, one or two people are trying to understand why, and seem to think the 1988 flywheel may be ok?

Any further info will be gratefully appreciated!!!!

[Mkelcy]

Take a look at the opening posts in this thread: http://www.camaros.net/forums/showthread.php?t=98387

The short answer is that the LT1 T56 uses a "pull" style clutch, rather than the more standard "push" style clutch, and the flywheel to which the pull style clutch bolts is substantially thicker than a standard flywheel.

[MinesGT]

Thanks for the quick reply Mike.

I do not know much about these engines as such, but would there be a balance issue?, or because the block is the later block is it a straight forward "bolt and play" with the LT1 flywheel?

again, many thanks

[Mkelcy]

If your 350 is a one piece rear main seal engine and internally balanced, I believe an LT1 flywheel would work.

[claytonisbob]

1988 should be 1 piece seal, and being so it should bolt right up. It is thicker, also a 350 should be (usually) internally balanced.

[MinesGT]

Again, many thanks for the replies.

At least i will be able to explain why, when i ask the suppliers!!

cheers

[WS6]

The LT1 engine is not an internally balanced. It is actually balanced by the flywheel. So this means you'll need to remove the weight that should be on the LT1 flywheel. It's on the opposite side from the friction face. I call this the back side but just wanted to be clear. Your 88 SBC, is it internally balanced? If not was it balanced by the balancer or the flywheel? You'll need to replicate the balance with the LT1 flywheel if the 350 was balanced by the old flywheel. If the 350 requires a zero balanced flywheel, have the LT1 flywheel checked and don't just depend on removing the weight off the back side to be accurate. If you're buying a new flywheel from say McLeod, you should be able to get a zero balanced LT1 flywheel or at least one that has the weight bolted on and not cast along with the flywheel as a factory piece is done.

[TitoJones]

Also it is a tiny bellhousing and will only fit a 153 tooth flywheel inside of it.

You can bolt an LT1 T56 flywheel to any 1 pc rear main seal SBC as they are typically internally balanced.

Tyler

[zman1969]

I may be wrong here but I believe the 1pc 350's are not zero balanced as the flex plates I have seen and replaced ARE counter weighted

[79ZED]

The LT1 style T56 uses a 153 tooth externally balanced one piece seal flywheel.

GM switched to a one piece seal on all their small blocks in 1986 which requires the externally balanced flywheel. The change to the crankshaft flange required that extra weight be added to the flywheel. All one piece seal small blocks are externally balanced.

If your engine is stock and hasn't been internally balanced, then the LT1 153 tooth flywheel will bolt right up and will work with your SBC 350.

No problem. You're good to go.

John