Replacing 2001 LM7 with an L33
Thread Starter
Teching In
Joined: Aug 2016
Posts: 13
Likes: 1
Replacing 2001 LM7 with an L33 Hello,
I am new to the forums and not sure if this is the correct spot.
I have a 2001 Suburban with 262,000 miles and the stock LM7 finally gave out this last weekend. I am trying to decide what to replace it with, I would like a little more power but do not want to loose any fuel efficiency, and do not want to make any modifications to anything.
From reading online I can not find enough definitive info. about replacing a 2001 LM7 with a 2005 or newer L33.
Can I use all my existing manifolds intake, exhaust and sensors and just remove the LM7 long block and drop in the L33 long block? Will everything bolt up without issue?
Will the PCM automatically adjust for the higher performance motor? Will my MPG decrease from going with the L33?
I appreciate any help and feedback.
Thanks
I am new to the forums and not sure if this is the correct spot.
I have a 2001 Suburban with 262,000 miles and the stock LM7 finally gave out this last weekend. I am trying to decide what to replace it with, I would like a little more power but do not want to loose any fuel efficiency, and do not want to make any modifications to anything.
From reading online I can not find enough definitive info. about replacing a 2001 LM7 with a 2005 or newer L33.
Can I use all my existing manifolds intake, exhaust and sensors and just remove the LM7 long block and drop in the L33 long block? Will everything bolt up without issue?
Will the PCM automatically adjust for the higher performance motor? Will my MPG decrease from going with the L33?
I appreciate any help and feedback.
Thanks
Thread Starter
Teching In
Joined: Aug 2016
Posts: 13
Likes: 1
Thanks, JoeNova I appreciate the info.
Have you done a swap like this?
Anybody else want to weigh in here as well?
Is there anything I am missing or not thinking of?
Has anyone here actually done this swap?
What were the actual results?
I am hoping that JoeNova is correct and I should not only gain HP but MPG as well, has anyone actually done this and can attest to gaining 1 or 2 MPG?
Have you done a swap like this?
Anybody else want to weigh in here as well?
Is there anything I am missing or not thinking of?
Has anyone here actually done this swap?
What were the actual results?
I am hoping that JoeNova is correct and I should not only gain HP but MPG as well, has anyone actually done this and can attest to gaining 1 or 2 MPG?
Thread Starter
Teching In
Joined: Aug 2016
Posts: 13
Likes: 1
Thanks JoeNova
I kinda figured that, I am just wanting to make sure I am making a good choice.
In your opinion does the L33 make the most sense for just the cheapest easiest way to swap with out having to open up a motor and still get decent hp gains for the money?
Or should I consider a used LM7 and do a ZO6 cam and spring upgrade?
I dont really want to mess with that though, I would like to just pull and replace and gain 25hp or so?
I have also heard that if I get a tune after the swap I could expect the HP gains to be even better?
But again I don't want to start affecting my MPG negatively.
I kinda figured that, I am just wanting to make sure I am making a good choice.
In your opinion does the L33 make the most sense for just the cheapest easiest way to swap with out having to open up a motor and still get decent hp gains for the money?
Or should I consider a used LM7 and do a ZO6 cam and spring upgrade?
I dont really want to mess with that though, I would like to just pull and replace and gain 25hp or so?
I have also heard that if I get a tune after the swap I could expect the HP gains to be even better?
But again I don't want to start affecting my MPG negatively.
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On The Tree
Joined: Oct 2011
Posts: 102
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From: Dirty South
Yes JoeNova is correct . The L33 offers weight savings , 243 heads , higher compression @ almost 10:1 , flat top piston floating pin , slightly bigger cam. L33 cam specs 193/193 .479/.479 116 vs LM7 190/191 .466/.457 114. The L33 cam is worth about 10 hp and 9 tq @ 5500 . Under the curve the cams perform pretty much the same.
Thread Starter
Teching In
Joined: Aug 2016
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Teching In
Joined: Sep 2022
Posts: 18
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From: Fairfax, VA
Hello, yes I completed this swap years ago. Everything and I mean everything will bolt right up to the long block without any issues. The only thing is I would recommend getting it tuned when you are done by Blackbear Performance. The factory tune for the LM7 will run the L33 just fine but a tune from Blackbear will make a difference.
Teching In
Joined: Sep 2022
Posts: 22
Likes: 10
Hello, yes I completed this swap years ago. Everything and I mean everything will bolt right up to the long block without any issues. The only thing is I would recommend getting it tuned when you are done by Blackbear Performance. The factory tune for the LM7 will run the L33 just fine but a tune from Blackbear will make a difference.
Good to hear. I'm doing the same but have a L59 engine (basically a LM7 flex fuel). But I also am adding shorty headers, cat delete, true dual exhaust w/ x pipe, a REAL cold air intake and a torqer truck cam. Swapping the L33 injectors for the L59's as they are 36.6# flex fuel and are good to 450hp+ So I'll definitely need a custom tune but should get same mpg just have a little more top end hp and bottom end torque.