1986 mcss 6.0 engine swap
Thread Starter
Teching In
Joined: Jul 2005
Posts: 34
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From: Palmdale, Ca
1986 mcss 6.0 engine swap I am putting a 6.0 into my 1986 mcss and was wondering about a couple of things. 1) Are there any changes in the wiring harness pins form the 2001 LS1 harness? 2) Does anyone know about mounting the 4l80e in a g-body car ? and Where I can get a crossmember? 3) Headers, Since the headers are form a 2002 silverado hd can I use these or can I go aftermarket? If aftermarket are there any thats smog legal since I am in california? And Last if the oil pan Street& Performance say the truck pan should work but I was wondering if it can be modified. (like shortend 2")
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
1. The truck harness pin outs are different from the car. I found them in a chiltons book at the library (well actually the whole wiring diagrams) The pin outs were on this site Search "Truck pin out`s " and they should come up. If you want a copy of the wiring diagrams I can send them as pdf. file if you pm me your e-mail address.
2. Try crossmembers.com I don`t know if they have one for a 4l80e though.
4. The truck oil pan will kind work but it is 2-3 inches too deep, I think it could be shortened but it would be a lot of work. A camaro pan is a closer fit. The mounts that I bought placed the engine for a direct fit, no cutting of oil pan or crossmember with a camaro pan.
2. Try crossmembers.com I don`t know if they have one for a 4l80e though.
4. The truck oil pan will kind work but it is 2-3 inches too deep, I think it could be shortened but it would be a lot of work. A camaro pan is a closer fit. The mounts that I bought placed the engine for a direct fit, no cutting of oil pan or crossmember with a camaro pan.
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
I bought the mounts from another member who was parting out his 6.0L cutlass. I have been meaning to measure the mounts so that I have the dimensions but have not had the time. If you want to see a pic of the mounts click the link and drag down about 3/4 of the page. https://ls1tech.com/forums/showthrea...4&page=2&pp=20 Also did you check out John B. `s page at montecarloss.com, he has the most thourough ls1 into g-body write up anywhere. 
Originally Posted by G-Body
I bought the mounts from another member who was parting out his 6.0L cutlass. I have been meaning to measure the mounts so that I have the dimensions but have not had the time. If you want to see a pic of the mounts click the link and drag down about 3/4 of the page. https://ls1tech.com/forums/showthrea...4&page=2&pp=20 Also did you check out John B. `s page at montecarloss.com, he has the most thourough ls1 into g-body write up anywhere.
What he said. If you have't been over to montecarloss.com its a must theres alot of info over there on the ls1 swap and what parts are needed and where to get them. John B's page has a great write up on it as well.
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Teching In
Joined: Jul 2005
Posts: 34
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From: Palmdale, Ca
Originally Posted by G-Body
I bought the mounts from another member who was parting out his 6.0L cutlass. I have been meaning to measure the mounts so that I have the dimensions but have not had the time. If you want to see a pic of the mounts click the link and drag down about 3/4 of the page. https://ls1tech.com/forums/showthrea...4&page=2&pp=20 Also did you check out John B. `s page at montecarloss.com, he has the most thourough ls1 into g-body write up anywhere.
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
The 6.0l is another version of the ls1, same basic design just cast iron block, different accessory mounting, intake manifold(you wont be able to use the intake cover well unless you cut a hole in the hood 
) and oil pan. You might luck out on the crossmember, I read that th200r4 crossmembers can be used with th400 trans, since the 4l80e is a th400 with OD chevy probably kept the mount location the same, you could check the dimensions at the TCI transmissions site.
) and oil pan. You might luck out on the crossmember, I read that th200r4 crossmembers can be used with th400 trans, since the 4l80e is a th400 with OD chevy probably kept the mount location the same, you could check the dimensions at the TCI transmissions site. 
On The Tree
Joined: Mar 2003
Posts: 153
Likes: 0
From: Mechanicsville, VA
Not sure on a 6.0. I had John B. modify my Camaro oil pan and bought his motor mounts. Fit perfect. Went with a crossmember from G-Force, works well with 4L60E tranny. I also used Hooker headers (smog legal) for a camaro, drivers side fits perfect, pass. side needs coaxing. Wiring harness had Speartech modify the original one. And last 3" true dual exhaust from Torque Tech, gives you the option to come out rear like original or out side behind tires(my option). Buy the tech manual for your donor eng. INVALUABLE!!!!
Last edited by 86MonteSSLS-1; Jul 29, 2005 at 08:17 PM.
Staging Lane
Joined: Nov 2003
Posts: 80
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g force If you take some measurements, G-Force can fab you a crossmember with the dimensions you send.
They quoted me 320.
Mine bolted right in, all I had to do was drill 2 holes for the frame extension (mine's an 83 Elky).
It's a nice piece.
They quoted me 320.
Mine bolted right in, all I had to do was drill 2 holes for the frame extension (mine's an 83 Elky).
It's a nice piece.
