Milling 317's down to 58cc
06-02-2009, 07:25 AM
#1
Milling 317's down to 58cc Possible and recommendable? I know the deck will be thin for boost though. Here is the deal.
I have 20cc dished Diamond pistons with a stock 6.0L MLS gasket at .054 on a 3.906 bore 4.00 stroke. I am coming up with a 58cc head to get me to 9.75:1 compression where I want to be. I have some really nice CNC and hand finished 317 heads from TPIS though that I want to use with 2.08 and 1.60 valves. Is it possible to get them down that far?
I have 20cc dished Diamond pistons with a stock 6.0L MLS gasket at .054 on a 3.906 bore 4.00 stroke. I am coming up with a 58cc head to get me to 9.75:1 compression where I want to be. I have some really nice CNC and hand finished 317 heads from TPIS though that I want to use with 2.08 and 1.60 valves. Is it possible to get them down that far?
Last edited by Z06PSI; 06-02-2009 at 07:34 AM.
06-02-2009, 07:32 AM
#2
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i would look at other options. i think (no actual experience) that if you mill them alot you will have alignment issues. taking out 14 cc's will require quite a bit of milling. maybe someone that has milled them down a bunch can confirm.
06-02-2009, 07:36 AM
#3
Yeah this is a little frustrating but I wont go into details. Basically I need a 58cc head to get my compression where I want it with good flow because I have a KB 2.8L blower on a 383 stroker. Cam is a 225/233 with .585 lift and I want to maximize what I have.
06-02-2009, 07:36 AM
#4
You'll have to mill the 317s close to .085" to get 58cc. Possible, yes. You'll probably compromise your low and mid-lift flow with that much of a mill and possibly get into some intake alignment and valvetrain geometry issues too. I think you could get some decent coin for those 317 heads and put it toward some nicely ported small chamber heads.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
06-03-2009, 01:20 PM
#5
Is the engine assembled? If not sell the pistons and get a new set. You'll probably walk away paying the same. I Just sold a set of diamond pistons brand new with a -7cc dish that would have been high 9ish:1 compression with a 3.905 bore and a 4" stroke. I sold them for $400 shipped. So if your pistons are new, you should be able to sell them.
06-03-2009, 04:32 PM
#7
It's not going to work. That's more like a .098 mill aka a **** ton. You'd have major alignment issues with that kind of mill. You'd also be shrouding the valves even more by the reduction in chamber size. The more you mill the closer the chamber walls come to the sides of the valves.
With 2.08, 1.60s, the milling, and the small bore it would basically kill the heads. Even a TFS 235 is way too large. The minimum recommended bore for those is 4.03 which is far from your 3.90x. I would sell the heads you have and get a nice set of 5.3 heads from TEA. Their stage 1 and 1.5 are a great head for the money. You would also only have to mill those a very small amount to get them to where you want them to be.
What vehicle are you putting this in?
With 2.08, 1.60s, the milling, and the small bore it would basically kill the heads. Even a TFS 235 is way too large. The minimum recommended bore for those is 4.03 which is far from your 3.90x. I would sell the heads you have and get a nice set of 5.3 heads from TEA. Their stage 1 and 1.5 are a great head for the money. You would also only have to mill those a very small amount to get them to where you want them to be.
What vehicle are you putting this in?
