289 overbore max

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Mar 13, 2003 | 07:54 PM

66 Ranger

Thread Starter

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Joined: Jan 2002

Posts: 593

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From: Texas panhandle

289 overbore max

A friend offered me a 66 289 block 'free for hauling it off'. It's been bored .040 oversize. What is the recommended max overbore for this engine? I know it's probably been discussed before in this forum but this is the first time I've checked in here. I'm usually in the FE forum. Thanks for the responses.

Mar 14, 2003 | 11:49 AM

TorqueKing

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Joined: Feb 2002

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From: Atlanta, Georgia, USA

289 overbore max

I've seen racers get away with .060" overbore, but not for street driven engines, it's cutting way too close to the water jackets on a stock block, and you'd see a lot of overheating with constant use. 040" is usually the maximum safe bore for Windsor blocks, with the exception of the new Dart Iron Eagle blocks, which can take up to 4.185", and I've heard the Motorsport block goes up to 4.125".

Mar 15, 2003 | 12:35 PM

Quantrex

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Joined: Jun 2002

Posts: 423

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From: Oklahoma

289 overbore max

Take the block and have it sonic checked. That will tell you for sure how big you can go. I've seen several 289's taken to +.060"; some have problems, some don't. Be sure you use a torque plate when boring and honing.