Shops, Barns, Varmints, and Trucks - Flywheel for SBC 400 and TH350,,,,

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Flywheel for SBC 400 and TH350,,,,

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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=211361
Printed Date: 17 Sep 2026 at 5:47pm
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Topic: Flywheel for SBC 400 and TH350,,,,

Posted By: desertjoe
Subject: Flywheel for SBC 400 and TH350,,,,
Date Posted: 14 Jun 2026 at 6:28pm

I'm gonna be needing a flywheel for my 1955 Chevy with a SBC 400 and a TH350. The engine is from a 1985 trk and the TH350 is also from a 1986 trk but not same trk as the 400 donor. I see where they make a 168 tooth and a 153 tooth,,,??

Replies:

Posted By: Ed (Ont)
Date Posted: 15 Jun 2026 at 6:36am

Make sure you get the flexplate for the 400 engine. They are externally balanced. One from a 350 engine will not do even tho it bolts up fine. Converter will bolt up to either plate as they have couple different patterns on the flexplate.

Posted By: desertjoe
Date Posted: 15 Jun 2026 at 6:53am

Well,,Thankee Kindly Ed,,,,!!

What is the difference in application from the 153 tooth to the 168 tooth flywheels,,,? Amazon lists both as for the 400 SBC,,,?

Posted By: TedN
Date Posted: 15 Jun 2026 at 9:54am

If I remember correctly the early V8s used a cast iron bellhousing and the smaller flywheel, and the started mounted to the bellhousing. In later years they needed a bigger clutch so they went to the larger flywheel/flexplate, although they kept using the small one in some vehicles for clearance issues. They also went to a block mounted starter, mounting holes are straight across for the small one, staggered for the large one. Your engine likely had the large one from the factory, and that is what I would put on it. I seem to remember there was something different about the 400 starters but I could be remembering things that aren't true.
Edit to add I don't think the 400 ever came from the factory with the small flywheel/flexplate.

Ted

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190XTD seriesIII, 190XTD seriesI, maroon belly 7000, 7030, 7045, D14, 190XTD series??? project(or maybe parts)