Rule of thumb on 243 mill measure?

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Jan 13, 2023 | 09:03 AM

bthomas

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Rule of thumb on 243 mill measure?

I recall reading before a measurement point on 243 heads that gave a pretty close idea to determine how much they had been milled.

Can’t seem to find anything about it now though.

Jan 13, 2023 | 10:14 AM

RonSSNova

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I believe the correct measurement is from the valve cover rail to the head gasket surface.
Another place would be the head bolt boss.

I get 1.619” at the head bolt boss.
And 4.752-4.753 at the valve cover surface.
Measured on untouched 799 heads I have here.

Ron

Jan 14, 2023 | 05:17 AM

Rick Dorion

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Is there similar info on other heads? Specifically, I'm interested in 862's.

Jan 14, 2023 | 12:51 PM

RonSSNova

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Since all heads are interchangeable, I would assume the 862 is the same measurement.

Jan 15, 2023 | 11:55 PM

Kawboom

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Quote:

Originally Posted by RonSSNova

This is good info, but I have a set of 243 heads that have been machined, I don't know how much but certainly not factory, and they measure 1.620". This measurement may not be consistent to the thousandth.