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ls7 heads on a ls2/3 block

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Old 11-08-2012, 11:49 PM
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Default ls7 heads on a ls2/3 block

anyone ever run ls7 heads on a ls2/3 block? Ive set them on both blocks and the intake valves clear the bores. The exhaust valves cleared on the 6.2 block but hit on the 6.0 block. Small exhaust valves could fix this. Just wondering if anyone has ever ran this combo?
Old 11-09-2012, 12:01 AM
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http://www.texas-speed.com/p-3948-pr...ore-heads.aspx
Old 11-09-2012, 01:35 AM
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its not just good enough to clear the walls but there needs to be some unshrouded
area around the valves to promote flow
4.100" is min bore
Old 11-09-2012, 04:05 AM
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Big valve heads on small bore = bad flow and fill characteristics.

If you dont have a 4.030+ bore then I wouldnt bother with square port heads at all youd be better off with cathedral.
Old 11-09-2012, 12:19 PM
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Stock GM Ls7 heads will not fit, BUT TSP does have a small bore Ls7 head BUT you need a 4.065(Ls3 size bore) or bigger to use them.
Old 11-09-2012, 12:43 PM
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Soo has anyone ran this combo before?
Old 11-09-2012, 05:58 PM
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Diet has them but on a 429 Ls3 stroker-E85? High comp and a 4L65/80 on a 5th Gen.
Old 11-11-2012, 03:52 PM
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actually GM is putting ls7 heads with 2.2-1.61 valves on a 4.065 bore in the new supercharged copo camaros. so it is possible on a ls3 block.
Old 11-11-2012, 07:50 PM
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https://ls1tech.com/forums/dynamomet...ore-c5z06.html
Old 11-12-2012, 09:29 AM
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yes people are and have done it on 4.00 bore w/ the exh valve change like you noticed
Old 11-12-2012, 05:51 PM
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Needs to be a 4.065 bore or larger for our heads. I would also not want to run these on a stock stroke LS3. It would kill a lot of low end that the stroker would really help pick up. If this is stock LS2/LS3 I would look pretty hard at our aftermarket casting LS3 heads. The 250 heads will flow as much as any stock casting ported with a 20-30cc smaller runner. Extra port velocity is pretty useful on those motors, as well as extra compression.
Old 11-12-2012, 06:34 PM
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LS7 heads are junk. You're better off with ported 241s.

Last edited by DietCoke; 11-13-2012 at 02:06 PM.
Old 11-13-2012, 02:31 AM
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Originally Posted by DietCoke
LS7 heads are junk. You're better off with ported 841s.
Are you sure there are 841 heads ???
Old 11-13-2012, 02:05 PM
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Originally Posted by lt1773
Are you sure there are 841 heads ???
I meant 241s, but it was sarcasm anyway
Old 11-13-2012, 02:23 PM
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Originally Posted by JohnJanz@Texas-Speed
Needs to be a 4.065 bore or larger for our heads. I would also not want to run these on a stock stroke LS3. It would kill a lot of low end that the stroker would really help pick up. If this is stock LS2/LS3 I would look pretty hard at our aftermarket casting LS3 heads. The 250 heads will flow as much as any stock casting ported with a 20-30cc smaller runner. Extra port velocity is pretty useful on those motors, as well as extra compression.
im thinkin using my stock non cncd hand ported ls7 castings...put new seats in them to run a smaller exh valve. Theyll be on a 4.005 bore, boosted. 4.125 crank. grp rods. 10.0compression. Will just run a huge exh duration to compensate for the smaller valve. something like 254/276 .680.680 115+3. single plane elbow 100mm tb. hope the **** fits haha

Last edited by 1bad lad; 11-13-2012 at 02:29 PM.
Old 11-13-2012, 02:33 PM
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thank you forfinding this!!
Old 11-13-2012, 09:37 PM
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no problem its my car lol.
Old 11-14-2012, 09:05 AM
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why not just use 799 or 243s
Old 11-14-2012, 11:51 AM
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Originally Posted by ngeno626
why not just use 799 or 243s
because you cant get 380+cfm out of a 243 head. not even close
Old 11-14-2012, 02:38 PM
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Dyno #s in sig. TSP small bores...


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