On a 408 block decked 0.022, heads milled 0.036 alignment problems
06-01-2006, 11:06 AM
#1
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On a 408 block decked 0.022, heads milled 0.036 alignment problems Hi all I’m trying out a few head combos on my 408, the block has been decked 0.022; I have a new set of 317 cast heads. I want to get my compression up to 11.5. Using a 0.042 gasket and I don’t want to change that gasket. PTV clearance will not be a problem.
1. With the block decked 0.022 is it possible to mill the heads down from 71 cc to 62cc a total of 9cc or 0.036 off so I end up with.
scr @ 11.5
dcr @ 8.14
2. With a total of 0.022 + 0.036= 0.058 will there be any alignment problems; I am using a 90 Fast manifold.
3. most likely the pushrods will need to be shorter @ 7.350
thanks.
1. With the block decked 0.022 is it possible to mill the heads down from 71 cc to 62cc a total of 9cc or 0.036 off so I end up with.
scr @ 11.5
dcr @ 8.14
2. With a total of 0.022 + 0.036= 0.058 will there be any alignment problems; I am using a 90 Fast manifold.
3. most likely the pushrods will need to be shorter @ 7.350
thanks.
06-01-2006, 12:28 PM
#3
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Originally Posted by slow trap
i don't know about alignment problems but you will probably need custom pistons or they will be around .030 out of the hole.
my main concern is the alignment of intake manifold and where they bolt into the heads. there was no problems with 0.022 of the block and non milled heads, just need to know if that extra 0.036 off the heads is a problem.
06-02-2006, 02:49 AM
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We experemented a little at another shop here in town and I cant remember the exact amount it was at when we had problems, but if you go too much the intake ports WILL NOT LINE UP...The intake will fall too low. I think it was around .030" but not sure... The best i can do for you is find out tomorrow what the maximum amount was that we were able to mill from the heads. Probably around 10:30 West Coast U.S. time tomorrow, i will post it if someone else already hasn't...
06-02-2006, 03:23 AM
#6
TECH Senior Member
On average it is .005 mill for every 1 cc (straight)
.036 mill would only be 7.2 cc
71- 7.2= 63.8
You would need a .045 mill to achieve 62 cc
Combine that .045 + .022 = .067
Therefore, Yes I believe you'll have allignement issues
.036 mill would only be 7.2 cc
71- 7.2= 63.8
You would need a .045 mill to achieve 62 cc
Combine that .045 + .022 = .067
Therefore, Yes I believe you'll have allignement issues
