At drive coupler

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Dec 28, 2016 | 10:59 PM

ftf396

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At drive coupler

Hi Guys. Are Chevy distributors interchangeable between bb and sm blocks? If so are the threads on the coupler different? I got a 90* adapter and it won't screw on tight, a lot of loose play but I can take a large screw with diff threads than the coupler and it will tighten up on the adapter. That's why I'm asking about interchangeability. As far as I know it's the original dist.but has no tag.
Thanks
Fred

Dec 28, 2016 | 11:24 PM

'75

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From: McHenry Illinois

Distributors are interchangeable. Are you talking about the tach drive?

Dec 28, 2016 | 11:39 PM

ftf396

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Quote:

Originally Posted by '75

Distributors are interchangeable. Are you talking about the tach drive?

Correct.

Dec 29, 2016 | 12:24 AM

TimAT

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From: Gladstone MO

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Check with Lars on that 90* coupler for the tach cable. As I recall, his take is the added load to drive the coupler wears the distributor gears like crazy. And there's a specification for setting up the distributor gear lash.

Dec 29, 2016 | 06:53 AM

Easy Mike

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From: Southbound

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If you correctly index your distributor, an adapter is not required. The stake mark on the distributor should line up with the stake mark on the intake manifold.

Dec 29, 2016 | 10:12 AM

lars

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From: At my Bar drinking and wrenching in Lafayette Colorado

Don't use the 90-degree coupler. The additional torque it takes to drive the coupler puts additional torque end thrust on the distributor crossgear, and you will get accelerated thrust surface wear in the housing, which will lead to gear failure on the crossgear and mainshaft.

There is no reason to use the 90-degree coupler. Simply install your distributor correctly per the GM Service Bulletin and your tach drive cable will have a free, straight shot. For info, send me an e-mail request for my paper "How to Install Your Distributor." It has photos and diagrams of the correct install.

Lars
V8FastCars@msn.com