Cylinder head questions
04-21-2006, 01:48 PM
#1
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Cylinder head questions & DCR
What's the max amount you can mill off a 317 (6.0) head? Also, is it .010 or .015 that you have to remove in order to lower the CC by 1 point?
Just wondering if there is any way to reach 66 or 68cc on a set of 317s?
Here is my dilemma;
I'm trying to get the best DCR ratio I can with the cam that I have. This is going to be a stock LQ9 with a TR230/224 111 cam.
Here is what I'm coming up with.
230/224 w/ 317s
DCR Ratio
72cc & .045 = 7.8 DCR <--- Obviously too low
68cc & .045 = 8.16 <--- Thinking about this, but is this still too low?
68cc & .040 = 8.26
66cc & .045 = 8.35
66cc & .040 = 8.46
SC Ratio
72cc & .045 = 10.36
68cc & .045 = 10.86 <--- *
68cc & .040 = 10.99
66cc & .045 = 11.13
If I can’t get the 317s to 68cc, my next option would be to go with LS6 heads correct?
Just wondering if there is any way to reach 66 or 68cc on a set of 317s?
Here is my dilemma;
I'm trying to get the best DCR ratio I can with the cam that I have. This is going to be a stock LQ9 with a TR230/224 111 cam.
Here is what I'm coming up with.
230/224 w/ 317s
DCR Ratio
72cc & .045 = 7.8 DCR <--- Obviously too low
68cc & .045 = 8.16 <--- Thinking about this, but is this still too low?
68cc & .040 = 8.26
66cc & .045 = 8.35
66cc & .040 = 8.46
SC Ratio
72cc & .045 = 10.36
68cc & .045 = 10.86 <--- *
68cc & .040 = 10.99
66cc & .045 = 11.13
If I can’t get the 317s to 68cc, my next option would be to go with LS6 heads correct?
Last edited by Zick; 04-21-2006 at 03:02 PM. Reason: Tried to edit title but didn't work. :(
04-21-2006, 04:27 PM
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Pretty sure that the 317's are a large chamber version of the LS6 and LS2 heads. You might be better off going with a LS6 or LS2 heads. Those are 62-64cc chambers, right? You could polish the chambers and maybe remove a little material to end up at 66-68cc's
04-21-2006, 04:30 PM
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Originally Posted by Keith
Pretty sure that the 317's are a large chamber version of the LS6 and LS2 heads. You might be better off going with a LS6 or LS2 heads. Those are 62-64cc chambers, right? You could polish the chambers and maybe remove a little material to end up at 66-68cc's
Milling the heads .035" will get the chambers down to 68cc. It would take a milling of .045" to get the chambers to 66cc.
04-21-2006, 06:08 PM
#5
Originally Posted by Zick
What's the max amount you can mill off a 317 (6.0) head? Also, is it .010 or .015 that you have to remove in order to lower the CC by 1 point?
Just wondering if there is any way to reach 66 or 68cc on a set of 317s?
Here is my dilemma;
I'm trying to get the best DCR ratio I can with the cam that I have. This is going to be a stock LQ9 with a TR230/224 111 cam.
Here is what I'm coming up with.
230/224 w/ 317s
DCR Ratio
72cc & .045 = 7.8 DCR <--- Obviously too low
68cc & .045 = 8.16 <--- Thinking about this, but is this still too low?
68cc & .040 = 8.26
66cc & .045 = 8.35
66cc & .040 = 8.46
SC Ratio
72cc & .045 = 10.36
68cc & .045 = 10.86 <--- *
68cc & .040 = 10.99
66cc & .045 = 11.13
If I can’t get the 317s to 68cc, my next option would be to go with LS6 heads correct?
Just wondering if there is any way to reach 66 or 68cc on a set of 317s?
Here is my dilemma;
I'm trying to get the best DCR ratio I can with the cam that I have. This is going to be a stock LQ9 with a TR230/224 111 cam.
Here is what I'm coming up with.
230/224 w/ 317s
DCR Ratio
72cc & .045 = 7.8 DCR <--- Obviously too low
68cc & .045 = 8.16 <--- Thinking about this, but is this still too low?
68cc & .040 = 8.26
66cc & .045 = 8.35
66cc & .040 = 8.46
SC Ratio
72cc & .045 = 10.36
68cc & .045 = 10.86 <--- *
68cc & .040 = 10.99
66cc & .045 = 11.13
If I can’t get the 317s to 68cc, my next option would be to go with LS6 heads correct?
They seem to relate the size CC and then the amount to mill to reach desired compression but it doesnt say what motor its on, deck height, piston dish etc... all that info is need
DCR is mainly concerned with the intake valve closing on the comp. stroke so its sset by the cam, you need to know valve events to figure that
04-21-2006, 06:33 PM
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Whats the deck height of the LQ9?
I know some LS1's have their pistons abouve the deck. Same thing with the LQ9?
I'm trying to run the numbers in the DCR calculator I have.
I know some LS1's have their pistons abouve the deck. Same thing with the LQ9?
I'm trying to run the numbers in the DCR calculator I have.
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04-21-2006, 10:46 PM
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Originally Posted by 02sierraz71_5.3
You can mill however much you want its just a matter of p/v clearance with some cams. Where did you get those specs?
They seem to relate the size CC and then the amount to mill to reach desired compression but it doesnt say what motor its on, deck height, piston dish etc... all that info is need
DCR is mainly concerned with the intake valve closing on the comp. stroke so its sset by the cam, you need to know valve events to figure that
They seem to relate the size CC and then the amount to mill to reach desired compression but it doesnt say what motor its on, deck height, piston dish etc... all that info is need
DCR is mainly concerned with the intake valve closing on the comp. stroke so its sset by the cam, you need to know valve events to figure that
I've got a DCR calculator and everything I need to know for it is listed on the cam card.
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