# LS2 to LS7 swap



## Freddykaye (Feb 5, 2010)

Its been a while since I've been here, I was forgotten... I just recently aquired an LS7 Crate engine, I was told the ECM from my LS2 would work but it had to be re-flashed yes? The other problem is I sold my LS 2 to a guy without flashing my ECM back to stock before pulling the engine. I have a diablo sport programmer running a custom tune. I had taken my Car in to the dealer to have some service done a while back and they couldnt access my ECM until I uploaded the stock program back into the ECM. Can I do it now without the engine? or after I install the LS 7? I think the guy I sold the engine to wants my ECM for my old engine. Any suggestions or advice? Thanks...


----------



## Tomh (Feb 1, 2010)

Freddykaye said:


> Its been a while since I've been here, I was forgotten... I just recently aquired an LS7 Crate engine, I was told the ECM from my LS2 would work but it had to be re-flashed yes? The other problem is I sold my LS 2 to a guy without flashing my ECM back to stock before pulling the engine. I have a diablo sport programmer running a custom tune. I had taken my Car in to the dealer to have some service done a while back and they couldnt access my ECM until I uploaded the stock program back into the ECM. Can I do it now without the engine? or after I install the LS 7? I think the guy I sold the engine to wants my ECM for my old engine. Any suggestions or advice? Thanks...


I run my ls3 off the ls2 ECM. just had to use the LS2 crank sensor (and ls2 crank). not sure of the # of teeth on the ls7 crank wheel... you probably would want to talk to who ever is going to tune it or maybe just pick up an LS7 ECM.... sounds like you have to give up the LS2 ECM to the new engine owner regardless?


----------



## Poncho Dan (Jun 30, 2009)

You'll need the oil pan off the LS2 to make the LS7 fit in the GTO.


----------



## Tomh (Feb 1, 2010)

Poncho Dan said:


> You'll need the oil pan off the LS2 to make the LS7 fit in the GTO.


does the LS7 block have a receiver for the dipstick? I plugged the one on my LS3 block and just used the receiver on the LS2 pan. something to consider before you get half way done with it.


----------



## GM4life (Mar 18, 2007)

Freddykaye said:


> Its been a while since I've been here, I was forgotten... I just recently aquired an LS7 Crate engine, I was told the ECM from my LS2 would work but it had to be re-flashed yes? The other problem is I sold my LS 2 to a guy without flashing my ECM back to stock before pulling the engine. I have a diablo sport programmer running a custom tune. I had taken my Car in to the dealer to have some service done a while back and they couldnt access my ECM until I uploaded the stock program back into the ECM. Can I do it now without the engine? or after I install the LS 7? I think the guy I sold the engine to wants my ECM for my old engine. Any suggestions or advice? Thanks...


You can make the LS7 work with the LS2 ECM if the Crank reluctor wheel has the same tooth count. LS7's use a 58x, early LS2's in GTO's and a few others used 24x reluctor.


Poncho Dan said:


> You'll need the oil pan off the LS2 to make the LS7 fit in the GTO.


He'll need more than that. The LS7 has a longer crank snout to drive the three stage oil pump. He will also need the front cover, and oil pump off of the LS2 also. Thats if he plans on going wet sump.


----------



## Poncho Dan (Jun 30, 2009)

Interesting, good to know.


----------



## 87GN06GTO07IRL (Aug 10, 2009)

Freddykaye said:


> I have a diablo sport programmer running a custom tune. I had taken my Car in to the dealer to have some service done a while back and they couldnt access my ECM until I uploaded the stock program back into the ECM. Can I do it now without the engine?


Yes. All you need to do with the diablo is to have the key on to change tunes.


----------



## 6QTS11OZ (Mar 27, 2005)

Okay OP. You've gotten some great advice. Care to comment?


----------

