help with milling heads , pushrod compression

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Apr 16, 2007 | 01:13 PM

Bader-X

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From: Kuwait

help with milling heads , pushrod compression

Hi
I calculated that a .20 mill of 806 heads is about 5 mm taken off the bottom head surface wich is about half a centemeter ... is this correct and what will the chamber cc be after milling? (and how about .15-.10-.25 while your at it

)

I have a 98 with a tr224 with 7.400 with that much of milling what will the compression be (with stock gaskets) and will I have to change to a shorter pushrod (7.350 or 7.375) just guess and help me I know a pushrod lenth checker but that`s not a practical method here (the only available are 7.400 and when the engine is opened can`t wait for more than a week for this to come).

thanks and if you provide the formulas and/or examples for other users help in searches then thanks even more.

Apr 16, 2007 | 01:18 PM

brad8266

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.020 mill you knock off about 3-4 cc's of chamber volume, which is 60-61cc on a 806 head IIRC.

Apr 16, 2007 | 01:54 PM

GR33N GoblinM6

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i thought 806 heads were 69cc's to start... not 64cc to start...

and i thought the 241 heads were 67cc's... and you mill .007 to take off 1cc.. so .021 to get to 64cc's on a 241 head...

is this not right?

Apr 16, 2007 | 02:04 PM

brad8266

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Quote:

Originally Posted by GR33N GoblinM6

i thought 806 heads were 69cc's to start... not 64cc to start...

That may be true, im not sure, I do know they are 5.3L heads and my 5.3's were 64cc's.

Apr 16, 2007 | 02:16 PM

GR33N GoblinM6

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From: Utah

806's are 5.3 heads? ive never seen a or head of a 5.3 head having casting # 806.. as far as i know the 806 heads were only used on 98 Fbody's and have a 69cc chamber.. the 853's were on the 99-00 cars.. and the 01-02 cars got the 241 67cc heads..

only head i know of with stock 64cc's is the 243 LS6 heads...

anyone else please confirm or set this straight?

Apr 16, 2007 | 03:06 PM

Phil'sC5vette

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On my stock LS1 heads and my TR224, the 7.40 seemed to work fine.

When I had the 228R installed under AFR 205s milled -0.020, I should have changed to 7.425 rod lengths. I did picked up some valve train noise between the cams.