max psi on stock heads?
10-18-2011, 10:46 PM
#1
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max psi on stock heads? in the middle of a turbo build and was gonna do a forged 5.3 with 317s for heads. i was told that if i wanted to run 14lbs of boost i would need diff heads because they will lift and blow heads gaskets from the thickness of the head being to thin. anyone have any luck running 14 lbs or higher with stock heads and it not blowing head gaskets every thousand mile?
10-18-2011, 11:44 PM
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Mls gaskets lasted for approx. 3k+ miles on my set up 11-12 psi. A lot of spirited driving on it as a daily driver. Turns out I was hitting 17-18#'s overboosting and #7 cylinder side of head gasket leaked out.
LS9 head gaskets are on now on the same 317's and with a very mild tune I was spinning out on the dynojet to 922whp/860wtq on 91 octane no meth.
A good tune goes a long way literally.
LS9 head gaskets are on now on the same 317's and with a very mild tune I was spinning out on the dynojet to 922whp/860wtq on 91 octane no meth.
A good tune goes a long way literally.
10-19-2011, 07:06 AM
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Mls gaskets lasted for approx. 3k+ miles on my set up 11-12 psi. A lot of spirited driving on it as a daily driver. Turns out I was hitting 17-18#'s overboosting and #7 cylinder side of head gasket leaked out.
LS9 head gaskets are on now on the same 317's and with a very mild tune I was spinning out on the dynojet to 922whp/860wtq on 91 octane no meth.
A good tune goes a long way literally.
LS9 head gaskets are on now on the same 317's and with a very mild tune I was spinning out on the dynojet to 922whp/860wtq on 91 octane no meth.
A good tune goes a long way literally.
Slow93z, I think you would be safe under 20psi. I believe it also depends on your CR.
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10-19-2011, 03:15 PM
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@gimmeluvin
8.5:1 cp's
72cc PRC stg. III 2.08/1.60 ported from TSP. (317's)
Comp 236/242 .610/.612 lift 114 lsa 12.5 degrees of overlap IIRC.
103# hi imp. injectors.
I really never intended to hit 18#'s. Was a mistake actually. lol.
13#'s for -DD
8.5:1 cp's
72cc PRC stg. III 2.08/1.60 ported from TSP. (317's)
Comp 236/242 .610/.612 lift 114 lsa 12.5 degrees of overlap IIRC.
103# hi imp. injectors.
I really never intended to hit 18#'s. Was a mistake actually. lol.
13#'s for -DD
10-19-2011, 04:32 PM
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lol. Yeah, after I read your last post again I realized that. 5k I am seeing 12-13#'s and no track times yet till I get a second vehicle. I can't risk breaking stuff right now. I still have 150 progressive NX system I am eagerly waiting to try out.
10-19-2011, 05:57 PM
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cool! thanks guys. but a far as running 14lbs. can it be done reliably? or do you blow head gaskets every couple thousand miles? and i guess the ls9 gaskets are the go-to gasket now..?
10-19-2011, 09:07 PM
#16
I built hot parts for friends swap, it uses a tnetics tc78 and has seen over 15psi daily for about 2yrs now. It's a stock everything bottom
end, stock heads milled .005 ls9 gaskets.new stock headbolts. Hell it's got a cl find tq converter we found for 50$. It's using s rebuilt th350. Runs hard everyday no problems. Excellent SD tune and 60lb injectors. Also using a 100$ C5 intake manifold
end, stock heads milled .005 ls9 gaskets.new stock headbolts. Hell it's got a cl find tq converter we found for 50$. It's using s rebuilt th350. Runs hard everyday no problems. Excellent SD tune and 60lb injectors. Also using a 100$ C5 intake manifold
10-20-2011, 01:00 AM
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Shoot for a HP/TQ goal. It's easier that way. Too many variables with boost. You can accomplish a certain boost goal but from my experience, the less air flow resistance from said parts the more power you can get per amount of boost.
Last edited by LSevil1; 10-20-2011 at 01:06 AM.
10-20-2011, 08:10 AM
#20
I have heard 241's are good because they have a thick deck. Correct me if I'm wrong. I got a lq4 390 sitting in my living room right now haha. I'm putting my ls1 heads on it which are 241.