LS7 swap for an LS3
Safety Car
Joined: Oct 2006
Posts: 3,602
Likes: 3
From: Cincinnati OH
+1
for the money of a GMPP crate motor, you have a LOT of aftermarket options that will par or outperform an OEM LS7. So it depends on how much "OEM" is really worth to you....
(built up or sleeved LS3, cam/heads, FI, how fast do you want to go?).
for the money of a GMPP crate motor, you have a LOT of aftermarket options that will par or outperform an OEM LS7. So it depends on how much "OEM" is really worth to you....
(built up or sleeved LS3, cam/heads, FI, how fast do you want to go?).
Safety Car
Joined: Sep 2007
Posts: 4,359
Likes: 6
From: Los Alamitos California
St. Jude Donor '09
+2
For the money you'll spend on a crate LS7, you can have a much better block with thicker walls. The thin walls of the LS7 don't give you as many options down the line. Katech's "budget" 427 would be on my list as would a lot of other solutions over a crate LS7 solution, especially for the money spent. The LS9 uses a 2009 LS3 block, not an LS7. Just my $0.02.
San
For the money you'll spend on a crate LS7, you can have a much better block with thicker walls. The thin walls of the LS7 don't give you as many options down the line. Katech's "budget" 427 would be on my list as would a lot of other solutions over a crate LS7 solution, especially for the money spent. The LS9 uses a 2009 LS3 block, not an LS7. Just my $0.02.
San
Melting Slicks
Joined: Jul 2007
Posts: 3,097
Likes: 5
From: Brentwood World's first A6 in the 9's (including N/A, blower, turbo and nitrous cars) 9.950@139.267 CA
The motor is physically the same size as the LS2/LS3 so everything is a direct bolt-in. I was able to use my LS2 headers which saved me the cost of having to sell them and buy proper LS7 ones and I figure I'm only losing about 5-10 rwhp as the exhaust ports are not all that much bigger.
Both motors were complete drop ins so with the exception of using the original AC compressor (to avoid having to recharge the system) I used all the accessories from the LS7.
The MAF and airbox is different from the LS2 but it's the same as an LS3 so I bought one from a buddy as well as the MAF/IAT sensor from the dealership.
There are some vacuum line differences so if they don't come with the crate motor you may have to order them from the dealership.
Although some people have done the swap by converting the engine to a wet sump system, that involves drilling the crank so I decided to install the full dry sump system. It's a PITA to mount properly because of having to cut out the battery tray but once you get it in there everything fits together pretty well.
I was originally going to relocate my battery in the back but ended up managing to fit a 17lb Braille battery beside the oil tank which saved me a fair bit of work.
The cam position sensor and MAF/IAT sensor wiring is different so you'll need one from a Z06 harness or they can be ordered from the dealership.
As for programming, that was probably the easiest part of the whole job. What I did in both of the swaps was to simply treat the engine as a larger displacement LS2 by copying over all of the engine parameters from a stock LS7 tune I downloaded from the HP Tuners website.
There are probably still a lot of details that I'm leaving out but this should at least hit the highlights of the process. PM or e-mail me if you have any more questions about it.
Christopher
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Intermediate
Joined: Aug 2012
Posts: 28
Likes: 0
From: Pahrump Nevada
Not sure if there is a newer thread than this... but I thought I would revive this one as I just grenaded my LS7 on the track this weekend.
I am thinking LS376/525 for 1/2 the money of an LS7. With all the $$$ to be saved can also put a proper dry sump system on the LS3 and still have 3 or 4 thousand left over.
Has anyone done this swap?
I am thinking LS376/525 for 1/2 the money of an LS7. With all the $$$ to be saved can also put a proper dry sump system on the LS3 and still have 3 or 4 thousand left over.
Has anyone done this swap?
Intermediate
Joined: Nov 2014
Posts: 45
Likes: 5
+2
For the money you'll spend on a crate LS7, you can have a much better block with thicker walls. The thin walls of the LS7 don't give you as many options down the line. Katech's "budget" 427 would be on my list as would a lot of other solutions over a crate LS7 solution, especially for the money spent. The LS9 uses a 2009 LS3 block, not an LS7. Just my $0.02.
San
For the money you'll spend on a crate LS7, you can have a much better block with thicker walls. The thin walls of the LS7 don't give you as many options down the line. Katech's "budget" 427 would be on my list as would a lot of other solutions over a crate LS7 solution, especially for the money spent. The LS9 uses a 2009 LS3 block, not an LS7. Just my $0.02.
San
