Best LS Swap Headers - For a 4X4?

[rowdy11]

Does anyone have information on good LS swap headers for a K10? My LS is an L96 out of a 2011 GMC Sierra. 823 heads.

I have been looking at Headman LS Swap Headers (69713) but everyone that sells them shrugs their shoulders when I mention this is for a K10, not C10. Same with Hooker or Doug Thorley's.

Thanks all!

[prodjay10]

Is the frame different on the K’s? I’d like to know this. I may just do a swap on my K15.

[mongocanfly]

Dont rule out using ls3 or tbss manifolds...they flow very well

[Captainfab]

What year is your K10? What trans and transfer case are you running?

[mongocanfly]

His build thread shows a 6l90/205 into a 70 model....

[Cledus Snow]

I have a 1973 K20 (GMC K25) with a LS L96, 6l90 and a NP205 transfer case. I did a lot of research and found two headers that work without any modifications.

Schoenfeld Headers - (#1302LS1)

Speed Engineering Headers - (#25-1025)

I'm not sure how much frame clearance difference the 1970 K10 frame has compared to 1973 K20 frame, but the Speed Engineering headers fit really nice and tight next to the engine block with plenty of room between the frame.

The Schoenfeld Headers fit a little closer to the frame.

Both manufacturers say on their website that the headers fit 2WD frames only, but both fit great, with enough room to run your exhaust around the transfer case.

[derotoreut]

I'm doing a 5.3L LM7 swap into my 1970 K10 with 4L60E/NP205. I'm using the Pacific Fab front cross member with engine mounts and the Advanced Adapter T-case kit. I originally tried the Doug Thorley THY-324Y-C. These were supposed to fit with no modification. On my application they hit the firewall. I decided to go with the Speed Engineering mid-length. I was nervous that the long tube headers would hang down too low and interfere with the transmission cross member. Plus Speed Engineering says the long tube headers are for 2WD only. These are what I went with:

https://www.speed-engineering.com/ls...c10-truck.html

Doug Thorley THY-324Y-C hit my firewall


Speed Engineering PN 25-1021 mocked up on truck

[rowdy11]

Thanks everyone for the responses so far. Yes Greg nailed it...NP 205/L96, K10 and I'm using a new Dirty Dingo motor mount setup for my swap. I still don't have the transmission crossmember figured out as those are as hard to find for a 4X4 6L90 as proper headers are...will probably have to fabricate something.

I appreciated the pictures and love the fit! I'm glad I decided against the Doug Thorley's. I ordered the Hedman headers and have them in a shipping box. I hope to have the engine mounted with headers this long Thanksgiving weekend although I'll be measuring against a cardboard firewall mockup.

I will send some pictures. Additional thoughts welcome as always.