Big boost with rectangular port heads? Step inside
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From: Thomasboro, ILL
Big boost with rectangular port heads? Step inside So i closed my season on a lean #7 cylinder, which made me tear into my engine sooner then expected. On inspection of my heads i noticed little cracks on the head between the valves. Im positive they werent there before installation. Im also switching around intake setup and have the chance to go to a rectangular port head. Ive searched for about a week now seeing no one really put a rectangular port head to the test of high boost. Many that see 10-12 psi, but im looking at 24-28 range. So who has put a LS3, LSA, LS9 head to the test? Would notice a power gain in the lower at lower boost levels with these heads? Or should i stick with my 317s?
Background on the car: 370, GT55-94, 25 psi average, E85, 1/2" ARP studs, LS9 gaskets . Current heads are hand hogged 317s that held up to over 75 20-28 psi passes, and probably hundreds of street pulls.
Background on the car: 370, GT55-94, 25 psi average, E85, 1/2" ARP studs, LS9 gaskets . Current heads are hand hogged 317s that held up to over 75 20-28 psi passes, and probably hundreds of street pulls.
The LSA and LS9 head would be much better than the 317s. Since you are setup for it, Id rock the LS9 because of the 1/2 head bolts. It will take a little machine work, but youll be happy with them.
We run 19-22 psi on the ZR1s with out issue and getting pretty crazy with the tuneup and water temps ( 25-27* timing and AFRs in the 13s on a road course)
Id stay FAR away from the 821 or 823 LS3 castings.
We run 19-22 psi on the ZR1s with out issue and getting pretty crazy with the tuneup and water temps ( 25-27* timing and AFRs in the 13s on a road course)
Id stay FAR away from the 821 or 823 LS3 castings.
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From: Thomasboro, ILL
The LSA and LS9 head would be much better than the 317s. Since you are setup for it, Id rock the LS9 because of the 1/2 head bolts. It will take a little machine work, but youll be happy with them.
We run 19-22 psi on the ZR1s with out issue and getting pretty crazy with the tuneup and water temps ( 25-27* timing and AFRs in the 13s on a road course)
Id stay FAR away from the 821 or 823 LS3 castings.
We run 19-22 psi on the ZR1s with out issue and getting pretty crazy with the tuneup and water temps ( 25-27* timing and AFRs in the 13s on a road course)
Id stay FAR away from the 821 or 823 LS3 castings.
The LSA and LS9 head would be much better than the 317s. Since you are setup for it, Id rock the LS9 because of the 1/2 head bolts. It will take a little machine work, but youll be happy with them.
We run 19-22 psi on the ZR1s with out issue and getting pretty crazy with the tuneup and water temps ( 25-27* timing and AFRs in the 13s on a road course)
Id stay FAR away from the 821 or 823 LS3 castings.
We run 19-22 psi on the ZR1s with out issue and getting pretty crazy with the tuneup and water temps ( 25-27* timing and AFRs in the 13s on a road course)
Id stay FAR away from the 821 or 823 LS3 castings.
Ill be cutting some heads apart tomorrow 
The LSA and LS9 heads are also a much better material.
The 317 vs the LS3, I have not the slightest clue. I have one of those too, Ill cut apart.
The LSA and LS9 heads are also a much better material.
The 317 vs the LS3, I have not the slightest clue. I have one of those too, Ill cut apart.
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My future plans definitely have the lsa heads included in them and have for a bit now. Seems to be the best bang for the buck going at the moment. I thought i read there's a minimum bore required of either 4.00 or 4.030. Can you confirm that as well Louis?
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From: Home town Clive,IA current town FORT BENNING GEORGIA
From the old beat to death L92 head threads seems like if you try and machine them to run 1/2" studs they break super easy under a decent amount of boost. I'm running standard diameter ARP studs and will see how far i can push my L92's with the GT-88
