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LS6 Intake Swap
8 Attachment(s)
LS6 intake swap
Heres a brief write-up on what all I’ve encountered during my swap to the LS6 intake Hopefully this will help others that would like to do this swap There are a few ways you can go about this so it’s kind of hard to make a step by step type write-up So I'll just stick to sharing my experience Intake You will need longer bolts or car bolts M6X100 110mm long Attachment 138299 The ls6 intake doesn’t have a nip that goes to the valve cover vent on the pass side I cut away as shown below, drilled and tapped with a 1/8 npt tap for a brass fitting (This was drilled at a slight angle) You may be able to tap a fitting into the intake tube “not sure though” Attachment 138300 Fuel rails and injectors I made a bracket for the fuel rails I used 1/8 X 1” steel stock, cut out for the injector bosses, Spacers welded on, drilled and tapped the spacers, drilled for the intake bolts and its good to go Attachment 138301 Injectors… Facts 1 The truck injectors will not fit inside the injector bungs on the intake 2 The seal kit (o rings) part number between the car and truck injector is different Heres why they don’t fit Attachment 138302 I removed the plastic tips on the injectors to clear the C shape at the bottom of the injector bung and replaced the lower Orings with the ones from an F body Water pump There are basically 3 different style water pumps out there The trucks' /press on pulley Attachment 138303 The cars'/ press on pulley Attachment 138304 And the 97 corvette, which has the bolt on pulley Attachment 138305 Since the outlet on the truck WP is up high the TB will hit the upper outlet (especially drive by wire TBs) I believe the cable driven TBs can get away with just cutting down the upper outlet "not sure though" Mine is DBW so I used the 97 vette WP I got it from NAPA reman "part number 58-544" And ordered a pulley from GM This moves the outlet location to the lower boss, which will clear the TB What’s the significance in the bolt on pulley? Simple, the difference in the truck and car accessories is different The car accessories push the belt alignment back towards the engine. The 97 vette WP will have to be spaced out approx. 3/4 to keep belt alignment in check. The bolt on pulley allows spacing pretty easily But still, there’s another issue, The tensioner bracket The vette water pump has a boss there for the 3rd bolt but its not tapped That’s a simple fix though Drill it, tap It, put a spacer between the tensioner and WP, and you’re done Use caution though You don’t want to bust through into the WP Attachment 138306 |
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Idler pulley
The stock location of the idler pulley will not clear the TB The pulley will need to be removed, relocated and the stock boss cut off for TB clearance Attachment 138307 this is how mine looked after cutting Attachment 138308 I originally bought the speartech bracket but it didn’t work with the 97 vette WP And belt routing I made my own bracket to place the idler lower and more to the right This lets me run the belt under the WP and clear the water pump outlet Heres what I made Attachment 138309 Attachment 138310 The speartech bracket will work fine if you have the equipment to modify the WP like they do This requires, to the best of my knowledge, Cutting and welding the upper outlet tube to make it a 90* And machining the water pump boss so it can be pressed in Or…drilling and welding it in I didn’t have the tools to machine the water pump and don’t like the idea of welding on the WP Thats why I chose the 97 vette WP and making my own bracket Heres what the belt routing will look like Attachment 138311 Throttle body There was one more clearance issue with the TB and WP The bottom of the TB needs to be shaved a tiny bit to clear the WP housing This can easily be done with a file or grinder (This should be true with all truck TBs but I’m not certain) Attachment 138312 EVAP There is no place to connect the truck EVAP canister to the intake the way it’s connected To the truck manifold I first removed the Oring on the outlet then I took the connector off the PCV hard line and clamped it to the outlet of the Canister I then used a reducer ½ by 3/8 And connected it all together with a 5/16 fuel line to the brass nip on the driver side of the intake PCV For this I just ran a 3/8" transmission cooler line from the hard line to the pass side of the intake Heres a pic of the vac linesAttachment 138313 FPR (Fuel pressure regulator, if equipped) I used a vacume line attached to existing line with rtv Back to the small nip at the very back of the intake Attachment 138314 I do not have results yet, but will soon:judge: What really made me do this swap is the theories I've had based on the results and powerband with my application as well as the design of the truck intake itself. It really came to the light when I compared Mattrem's dyno graph with mine A 228/230 should pull higher than a 216/220 with everything else being basically the same. I've also noticed this restriction in several other graphs I've seen It appears that 5000 and 350hp is the magic numbers where the intake begins to run out of breath I would also like to give Sportside a big thanks for getting my mind in the right direction with all of our back and forth PMs about reverse split cams, intake restrictions and so on After presenting the results and theories to Richard@wcch , he seems to agree and is interested in seeing the results :judge: Only one way to know for sure though, I should have track times and dyno graphs to compare the 2 soon:) I'll post results reguardless if its good or bad |
props to you for trying this out and the write up, hope there is a gain, seemed like alot of work you went through.. i want to see the dyno curves now.
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Interesting....and WAAAAAAY different from what I went through to put an LS1 intake on mine:
* My injectors dropped right in....with the exception of the height difference. my LS1 intake was a '98 though so later LS6's might be different * Manifold bolts were the same for both * MY LS1 intake had the PCV nipple already installed from the factory * TB cleared the WP housing without grinding * Cutting down the truck WP outlet to 3/4" tall and putting an elbow in worked for me Nice write-up though....VERY informative |
Good write-up. Getting ready to do a FAST intake myself. Can you take a better pic of what you do with the EVAP cannister? It's blocked in the pic.
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Originally Posted by Yelo
Interesting....and WAAAAAAY different from what I went through to put an LS1 intake on mine:
* My injectors dropped right in....with the exception of the height difference. my LS1 intake was a '98 though so later LS6's might be different * Manifold bolts were the same for both * MY LS1 intake had the PCV nipple already installed from the factory * TB cleared the WP housing without grinding * Cutting down the truck WP outlet to 3/4" tall and putting an elbow in worked for me Nice write-up though....VERY informative thanks for chiming in I take yours is cable driven from your previous posts and what you've told me through PMs Thats why I included that part about the cable driven TBs:) but unfortunately this doesnt work with the DBW's Thats crazy that its that much difference between the ls1 and ls6, especially the bolts:eek2: The fitting I threaded in goes to the pass. side valve cover vent From the best I can tell, The car had this on the TB where the trucks' is attached to the intake |
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Originally Posted by BenKey
Good write-up. Getting ready to do a FAST intake myself. Can you take a better pic of what you do with the EVAP cannister? It's blocked in the pic.
was take the connector off the hard line from the PCV clamped it to the stub that had the oring on it then reduced it with Attachment 138315 and let it feed into the brass nip on the front and driver side of the intake Ill try to get a better pic of it :judge: I may be going with a fbod type canister soon to clean things up a bit here it is Attachment 138316 |
Glad to see you got everything fabed up and on the truck, count me in for dyno/track day.
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Great post Kano!
Everything looks real nice too. I like your belt routing better than the speartech way. Are you using a stock length belt? Do you have any sketches for the idler bracket and fuel rail adapters? Also what did you do with that massive wire loom that goes over the top of the truck intake? Can't wait for the results. |
Originally Posted by 02sierraz71_5.3
Glad to see you got everything fabed up and on the truck, count me in for dyno/track day.
I hope I can make my first run at nam here pretty soon still waiting on the WP spacer ring and pulley to get back Im going to order another pulley and stock make my own spacers tomorrow Its been over 2 weeks now and Im tired of waiting Ill let ya know when she 's ready to roll:judge: |
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