L59 to L33 swap...

07sierraclassic

New member
Mar 11, 2012
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Buckley, WA
Ok so my truck has lost all compression on cylinder 7 so I'm looking to swap in the 5.3 HO. I'm thinking that it should be a direct swap obviously, but my question is do I have to use my L59 injectors due to the flex fuel shit or what? Also, will I need to tune it? Not a big deal cause I have access to HP tuners but this is my only vehicle so I want to get her back up ASAP. Anything I'm missing?

And yes, I would love to do a 6.0 swap but the money for a new trans I just don't have so 5.3 it is
 
I understand that a 6.0 will be essentially the same swap but the truck has high miles, and I don't have a lot of confidence in the trans lasting. L33 makes more sense for the situation I'm in now. I think...
 
computer will flash from current to 6.0, and yes you will need it tuned

my stock lq4, and 4l60 get along fine, and i beat the piss out of it, 120k miles.. rcsb tho, idk about a heavier truck :shrug:
 
Well we'll find out lol. I have a guy I work with that has HP tuners so I'm not too worried about it. Mine has an intake and exhaust right now so it's not built by any means, though I would like to cam it.
 
everything will swap over. Use ur pcm, engine will fire and run okay on 5.3 tune. But does need a tune to run properly.

Cam would really require a stall to take full advantage.
 
L33s never got my dick hard.
Junk yard 6.0 imo
Those flex fuels injectors will do fine on either setup

Buy 01+ lq4/9 it will bolt up.
Early motors had longer cranks that only bolt to 80es

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Beast shell,sprags,clutch packs etc.
Shift kit and vette servo added to will make you like it
It should do fine behind a tuned 6.ohhh

Buy a tru cool 40k from oregon performance
Stock trucks benifit

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Good to see some tech round heeyaa, i have yet to put my servo on my shortbed, maybe ill put it on my z71
 
Unless your gonna build trans just put a trans go shift kit, vette servos and as peyton said a big ass trans cooler

Exactly what I was thinking. I am worried about it lasting behind 380ft/lbs though, especially since I have 133,xxx miles on her already. I do have a trans cooler sitting in the garage I never got around to putting on the Obs. Hopefully picking it up tomorrow, swap next weekend. Does my 5.3 have the same 78mm throttle body? Anyone know what my injectors are rated at stock?