new intake on the block
the other thing i was thinking about, is if the dorman top shell is really that different, and that hump represents the overall shape of the top of the runner, than the dorman intake might have less runner cross sectional area and thus overall volume compared to the FAST.
yaaa I sold mine for 675 in all of 3 days with a stock tb and rails. Ls6 prices are going crazy 400 is easily attainable out of one, I guess I'm one of those fools 
thats great you got a good deal
thats great you got a good deal
I was going to get the ls6 for Christmas, but I think I'll wait for the ls2 and see how well it performs before I choose. Whichever can be home hand ported for the best results will be my pick.
Last edited by sawblade99Z; Dec 5, 2014 at 12:14 PM.
Thanks for posting that 5.3. And thanks to dreadpirateroberts for the pics.
The alignment of the ports look pretty poor, I'm wondering if they can be pushed into position.
Honestly, the dyno graph shows it's not that far behind the real LS6 manifold. If the tubes can be better aligned it might improve.
As expected, the F.A.S.T. is a better manifold.
The alignment of the ports look pretty poor, I'm wondering if they can be pushed into position.
Honestly, the dyno graph shows it's not that far behind the real LS6 manifold. If the tubes can be better aligned it might improve.
As expected, the F.A.S.T. is a better manifold.
Thanks for posting that 5.3. And thanks to dreadpirateroberts for the pics.
The alignment of the ports look pretty poor, I'm wondering if they can be pushed into position.
Honestly, the dyno graph shows it's not that far behind the real LS6 manifold. If the tubes can be better aligned it might improve.
As expected, the F.A.S.T. is a better manifold.
The alignment of the ports look pretty poor, I'm wondering if they can be pushed into position.
Honestly, the dyno graph shows it's not that far behind the real LS6 manifold. If the tubes can be better aligned it might improve.
As expected, the F.A.S.T. is a better manifold.
Now we need someone to pressure test it to 40lbs and see if it pops!
Last edited by Forcefed86; Dec 5, 2014 at 01:33 PM.
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Joined: Aug 2011
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From: Marengo, Ia
I've got to say I'm a little disappointed with those dyno numbers I expected the Dorman intake to be slightly ahead of the LS6, but it was close. That motor showed a 30 hp gain with a FAST 92 over the LS6, thats a pretty big gain showing that this motor can handle all the air it can get so it is going to magnify any loses in hp also. The Dorman was 7 hp down from the LS6 at peak thats only a 1.5% loss and could likely be made up with porting.
That was quick. http://www.onallcylinders.com/2014/1...ake-dyno-test/
way to go, dorman. not even on par with an LS6.
I'm wondering if there is anything sealing the to halves of the runners inside of the intake. If it's only sonic welded around the outside and nothing sealing up the inside that could cause some power loses. Internal leaks and poor parts alignment are what's wrong with the LS2 intake because on paper it's a better intake than the LS6.
honestly, looking at that test, that LS engine wasn't a stock motor. I'm sure the results would be within a couple of horsepower on a stock LS1 or LS6 between the OEM LS6 manifold and the dorman.
anyway, i really think the dorman-designed top shell is what's killing the whole manifold's performance.
if it were still possible to obtain a FAST 78/90 top shell, it might have been a worthwhile endeavor to cut the dorman top off, use the FAST top shell instead, and reseal everything with RTV. that would still be a ton of work, and in the end even if it was cheaper, you still could have purchased a FAST 92 new and saved yourself all the trouble.
anyway, i really think the dorman-designed top shell is what's killing the whole manifold's performance.
if it were still possible to obtain a FAST 78/90 top shell, it might have been a worthwhile endeavor to cut the dorman top off, use the FAST top shell instead, and reseal everything with RTV. that would still be a ton of work, and in the end even if it was cheaper, you still could have purchased a FAST 92 new and saved yourself all the trouble.
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Joined: Dec 2014
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From: Brimfield
Guys, I was lucky enough to see the piece that was dyno'd in that test. I was excited when I first saw it and somewhat disappointed when the results came back as I had hoped it would be as good as an LS-6. To answer some questions: Yes it is a little rough as produced, but it is also designed as an OE replacement part. Some flash removal and maybe some work to get the entrances close might add another 5-7. Also it is heavily glued together and I do not believe it would come apart without destroying it so porting would be difficult to say the least.-Mike
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Joined: Aug 2011
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From: Marengo, Ia
I still want to see someone pop the top off one and see whats going on inside the runners. But even without taking it apart there is still a lot of obvious improvements that can be made with some porting.
Joined: Aug 2007
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From: Turnin' Wrenches Infractions: 005
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Joined: Aug 2011
Posts: 1,324
Likes: 6
From: Marengo, Ia
also, the difference is closer to 10 hp according to that graph. that's significant in my opinion.
lastly, there is no data on a ported dorman yet. speculations on the performance of a ported unit are just that.