317 Heads on 5.7L
has a simular question but im thinking of running 317s on my boost build.
im not sure if im doing the math right or even if i have all the right data for the calculator casuse some of it is confusiong me.
does this look right for comprtession ratios and data.
LS1 standard sizes (i think)
Enter Cylinder Bore Size-----3.90
Enter Piston Stroke Length-------3.6
Enter Head Gasket Bore Diameter-------3.90
Enter Compressed Head Gasket Thickness----0.053
Enter Combustion Chamber Volume In CCs -----66.9
Enter Piston Dome Volume In CCs Negative For Dished Pistons (Use '-') ---0
Enter Piston Deck Clearance Negative If ABOVE Deck (Use '-') -----0.002
with this calculations,
Static CR is 10.16:1
now if this is correct now entering the 317 heads unmilled data with thinner gasket and this is what i got:
LS1 with 317 head sizes (i think)
Enter Cylinder Bore Size-----3.90
Enter Piston Stroke Length-------3.6
Enter Head Gasket Bore Diameter-------4.05
Enter Compressed Head Gasket Thickness----0.040
Enter Combustion Chamber Volume In CCs -----72
Enter Piston Dome Volume In CCs Negative For Dished Pistons (Use '-') ---0
Enter Piston Deck Clearance Negative If ABOVE Deck (Use '-') -----0.002
with this calculations,
Static CR is 9.8:1
Now if thats the right estimated calculation, would the 3 points of CR lost be even notice able? this slight drop in compression is what helps keep detonation down and able to crank up boost. Am I correct? need others with a bit more input.
I used this calculator for my reference. http://www.csgnetwork.com/compcalc.html
im not sure if im doing the math right or even if i have all the right data for the calculator casuse some of it is confusiong me.
does this look right for comprtession ratios and data.
LS1 standard sizes (i think)
Enter Cylinder Bore Size-----3.90
Enter Piston Stroke Length-------3.6
Enter Head Gasket Bore Diameter-------3.90
Enter Compressed Head Gasket Thickness----0.053
Enter Combustion Chamber Volume In CCs -----66.9
Enter Piston Dome Volume In CCs Negative For Dished Pistons (Use '-') ---0
Enter Piston Deck Clearance Negative If ABOVE Deck (Use '-') -----0.002
with this calculations,
Static CR is 10.16:1
now if this is correct now entering the 317 heads unmilled data with thinner gasket and this is what i got:
LS1 with 317 head sizes (i think)
Enter Cylinder Bore Size-----3.90
Enter Piston Stroke Length-------3.6
Enter Head Gasket Bore Diameter-------4.05
Enter Compressed Head Gasket Thickness----0.040
Enter Combustion Chamber Volume In CCs -----72
Enter Piston Dome Volume In CCs Negative For Dished Pistons (Use '-') ---0
Enter Piston Deck Clearance Negative If ABOVE Deck (Use '-') -----0.002
with this calculations,
Static CR is 9.8:1
Now if thats the right estimated calculation, would the 3 points of CR lost be even notice able? this slight drop in compression is what helps keep detonation down and able to crank up boost. Am I correct? need others with a bit more input.
I used this calculator for my reference. http://www.csgnetwork.com/compcalc.html
I used to run 317's before I went to ported 5.3's. Mine were decked .015 and from what TEA told me my c/i was low 9's and you would need to take a good chunk of metal off of them to get even close to 10.5. Also he mentioned how much the combustion chamber layout or something would hinder performance.
Like TJ said, check your ptv if you wish to run these heads with a large milling job. These are more of a boost head than a n/a head, hence why I switched.
Like TJ said, check your ptv if you wish to run these heads with a large milling job. These are more of a boost head than a n/a head, hence why I switched.
ive been playing with the CR calculator and im getting alittle more compression with certain numbers, for example
5.7L LS1 block, stock rotating assembly
317 heads - 72cc
different gasket thickness
cometics .040 w/ 4.010 gasket bore- 9.9:1 CR
LS9 gasket .051 - 9.8:1CR
Stock MLS gasket .056 - 9.7:1
so would a cometics gasket keeping the CR nearly close to stock CR be ok to run on moderate boost like 14psi?
5.7L LS1 block, stock rotating assembly
317 heads - 72cc
different gasket thickness
cometics .040 w/ 4.010 gasket bore- 9.9:1 CR
LS9 gasket .051 - 9.8:1CR
Stock MLS gasket .056 - 9.7:1
so would a cometics gasket keeping the CR nearly close to stock CR be ok to run on moderate boost like 14psi?
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Verdad Gallardo I myself have a 98 block with the the 98 heads with the graphite gaskets and notched heads still in the engine compartment from when gm put it in there lol. Plus i picked up a set of 317s cheap. Im running a gt45 turbo with at least 10psi when its all said and done. The cams a summit pro stage 2 turbo cam. By the math my cr will be roughly 9.8:1 on the old 5.7L and gives some room for tuning as well.
Staging Lane
Joined: Oct 2018
Posts: 78
Likes: 20
I am also wondering about this combo. I have a 1999 5.7 and a set of 317 heads as well as the stock 853s. I am replacing the 5.7 with a 6.0 and AFR heads so I have these leftover parts and don't want to give them away and thought I would set up a turbo engine for my next unknown project. Have you built this engine yet?
