2nd gen F-body w/6L80e????

[STV-R33D]

Has anyone done a LS swap in a 2nd gen F-body or any car really, using a LS2/6l80e combo? I ask because I'm trying to decide on what gear ratio to go with. This is a little over my head but first gear in this tranny is very deep (4.027:1) I'll be running Year One 17" Rally II's and having the stock 10 bolt rebuilt.

[1989GTA]

I guess that depends on the purpose of the car. With my 1965 Buick Skylark I wanted the motor to be turning around 1900rpm at 70mph for decent gas milage. With my Nitto 285/45ZR17 on the rear I went with a 3.27 ratio in my 8.5" ten bolt. With the low first gear it launches pretty good.

[cpd004]

I have the L99 6L80e combo in my G8 and it's perfect. It always felt better than my 98 Trans Am heads/cam/tuned car with modified 4L60e. If I could find a G8 combo reasonably priced I would jump on it for my 71. Had a lead a while back and it fell through.

[STV-R33D]

I got my engine and tranny out of a Caprise PPV cop car, so basically a G8. I had a G8 GT for 3 years, now have a GXP. The G8 has 2:92 gears but I'm not sure if that's the way to go? I'm putting this in a 1971 Formula, I don't plan on doing any racing.

[cpd004]

Has anyone done a LS swap in a 2nd gen F-body or any car really, using a LS2/6l80e combo? I ask because I'm trying to decide on what gear ratio to go with. This is a little over my head but first gear in this tranny is very deep (4.027:1) I'll be running Year One 17" Rally II's and having the stock 10 bolt rebuilt.

I read that this particular trans requires tunnel mods and can't get a straight answer on the accessories. Have you gotten any further info? I too am interested in the same swap in my 71.

[STV-R33D]

I read that this particular trans requires tunnel mods and can't get a straight answer on the accessories. Have you gotten any further info? I too am interested in the same swap in my 71.

I haven't read that anywhere YET and the place painting my car is taking their sweet old time so I haven't been able to place the engine and tranny in the car yet. I bought my LS swap kit from MR Muscle Rods http://www.brphotrods.com/products/2...cts/index.html ,because they are the only place that says their cross member works with the 6L80. I bought the entire kit including long tube headers and the F-body oil pan. They told me they mocked this kit up on a 1975 firebird. BUT...from what I've been reading changing the oil pan forces you to do a DOD/AFM delete...not a bad thing but that adds another $1500 to the cost of the motor if you can do the work yourself, not sure if I can? I would have been more than happy with a stone stock LS2, heck it has double the HP the transplanted 455 that was in this car.

So, my advise to you is if you can find a LS3 or non-DOD/AFM motor it may be worth the extra money upfront if you didn't plan to mod it.

[71maroesteban]

I tried to fit a 6l80e and no way was I gonna be happy with it. It's huge and the pan hangs super low even after I raised it 2 inches

[STV-R33D]

I tried to fit a 6l80e and no way was I gonna be happy with it. It's huge and the pan hangs super low even after I raised it 2 inches

Well...how about that...more good news :(

[cpd004]

I tried to fit a 6l80e and no way was I gonna be happy with it. It's huge and the pan hangs super low even after I raised it 2 inches

So I take it cutting is definitely required for use in a second gen f body?

[STV-R33D]

I did some searching this morning and most of the threads I found were a couple years old and it doesn't look like too many are using this trans?

My car was a 4-speed car and someone welded the tunnel up and put an auto in it and cut off the mounting tabs for the center console...no console was in the car when I got it, it was a drag car at one time so I have no problem getting it cut to fit.

I have a complete center console from a G8 that I wanted to fit into this car so since I have the engine and trany already I think I'll do whatever it takes to make it fit. Someone should do it right? LOL! I'm in no hurry.

[cpd004]

I did some searching this morning and most of the threads I found were a couple years old and it doesn't look like too many are using this trans?

My car was a 4-speed car and someone welded the tunnel up and put an auto in it and cut off the mounting tabs for the center console...no console was in the car when I got it, it was a drag car at one time so I have no problem getting it cut to fit.

I have a complete center console from a G8 that I wanted to fit into this car so since I have the engine and trany already I think I'll do whatever it takes to make it fit. Someone should do it right? LOL! I'm in no hurry.

Great! Keep us posted. It's a great trans. I have it in my G8.

[71maroesteban]

I tried to fit a 6l80e and no way was I gonna be happy with it. It's huge and the pan hangs super low even after I raised it 2 inches

So I take it cutting is definitely required for use in a second gen f body?

yes I had the sub frame off my car to figure out how it was going to fit and it's way to huge and the pan on it is huge! I measure it after I raised it nearly inches to get the same pan clearance as my current 350 Trans and I was going to need to cut the firewall trans tunnel opening and then tunnel but I was not going to be happy about raising my engine again nearly 4 inches so I sold it and will be going with a magnum. Was really hoping I'd work I mean a 6 speed auto with paddle shifters and trans breaking it's the best of both worlds sadly however oem transmissions haven't been to swap friendly as they are huge and most don't accept a slip yoke such as the tr6060

[cpd004]

This thread has some excellent info:
http://ls1tech.com/forums/conversion...o-does-go.html

[STV-R33D]

That is a good thread, too bad it wasn't a 2nd gen build. I read all 12 pages and was glad to see Speartech chiming in. I had them make my harness and tune my ECM, also went with their gauges.

I really need to get my car back so I can see how bad this thing fits.

[STV-R33D]

Well after six months I finally got my car back from paint. Contrary to what I've read in my own thread the 6L80e does fit in a 2nd gen F-body with no mods, at least it fits in my 2nd gen and that's the only one I need it to fit in! It's not hitting the tunnel any place and the pan is almost 5" off the ground and that's with low profile tires and a Ride Tech coil over front suspension.

[cpd004]

That's great news...it's an excellent trans.

What trans cross member and engine mounts are you using?

[STV-R33D]

I'm using the brphotrods kit. http://www.brphotrods.com/products/2...cts/index.html The engine mounts fit perfect no holes to drill but the cross member has fairly tall sides so I had to grind them down about 3/16ths because it was hitting the floor pans. It's still touching the floor pans but not enough to prevent me from tightening the body mount bolts. I'm also using Detroit Speed body mounts. The cross member mounting holes are not lining up very well with the plates that mount to the sub frame so I may just drill new holes?

[Zapper]

So we've just finished mocking up an LSA with a 6L90 and the trans pan sits far below the crossmember. I'm also running the Muscle Rods swap kit with their mounts and cross-member.

We are contemplating raising the whole set-up about 2" but throws of the angle of the trans to the rear end (ideal is 4 degrees)

Any input is appreciated and it seems no one makes a more shallow trans pan for the 6L90

[STV-R33D]

First I must tell you I'm not an auto mechanic, I'm doing this for the first time. I did read somewhere that some 6l80e & 6l90e's have deeper pans. My engine and trans came out of a Caprise PPV same as a Pontiac G8 GT. I read that this pan is the shallowest you can get. As you can see in the pics above the trans pan is only a little lower than the oil pan and the cars crossmember.

Maybe the pan from a G8 will fit on your tranny?

[bsharpe]

I'm surprised I haven't found this thread. I put a LS3 6L90 under my 71 trans am clone. The 6l90 is huge and has awful ground clearance. I raised my trans tunnel as much as 3" in some areas and raised most of the driveshaft tunnel. I have my motor a lot farther back which required more work. I honestly dont think the 6l80/6l90 will work well with out major modifications.



there isnt a shallow pan for the 6l90 but the shallow G8 pans can be modifed to work.