venomhp

iTrader: (13)

Hey everyone, Im just starting to have time and money here in the next 2-3 months to finally start working on our 72 cutlass. Right now my brother in law and I are debating which LS set up to run. We are aiming for 4-450 rwhp once done and have been debating an lq4/lq9 setup with the 4l80e trans and doing a H/C/I swap but recently have been thinking about an l92 and 6l80e/90e swap. I understand the 6spd is much thicker but it would be a sick set up and not require H/C or converter right off the bat so the price difference would be minimal between the two. What are your experiences with these set ups?

tippy

iTrader: (1)

Well, I recall when I was researching the 6l80E the only weakness I could find was the clutches and steels. Heard they liked to weld themselves together once the bumped up the power levels so upgrading those would be a good idea.
I have an entire drive-train with just exactly that setup in the classifieds.
Circle D is heavy into the 6l80Es.

John McGraw

I have done both and find the 6L trans to be a much better trans. The downside is that while the 4L will fit in most tunnels, the 6L will require surgery to the tunnel of most early cars. My 67 Chevelle required major cutting of the firewall and tunnel. The end product was worth all the work!


Regards, John McGraw

venomhp

iTrader: (13)

Well right now we dont have the space to do an entire frame off restoration, so in our 2 car garage this will be going down. I would rather not have to do any metal work to the firewall or tunnel unless its minimal and can be done relatively easy. I dont mind jacking the body off the frame because I want to get under there and clean it up but I was kind of hoping to make it an easy engine/trans swap with out extensive mods. From reading all of the threads here it looks like the LQX/4l80e setup would do that but if its minimal sheet metal work then I may be up for it, does anyone know around how much work is necessary for the 6spd?

hookemdevils22

iTrader: (12)

From a pure power perspective, the 4L will easily handle your expected output. If you are seriously concerned with hacking up the floor, stick with the 4L. It was a tight fit in my 71 Nova (even required fabbing my own 90* hose fittings), and I'm sure it'll be the same for the cutlass. I didnt have to touch the floorpan though.

venomhp

iTrader: (13)

If I had more space for the project I wouldnt care about hacking up the floor really since its all covered anyway but since I will be limited on space it would be much more difficult. I would really like the 6spd just because of the cool factor and knowing its the newest thing out there you know what I mean. Other than that the 4l80 would be great with a stall shift kit and cam. Im hoping for 425-450 to the wheels once all said and done. I also want to keep the factory shifter, I guess Ill cross that bridge when I get there but hopefully its not too bad- Thanks

350SS

iTrader: (38)

I'm sure you've seen it but just in case TCI has a conversion kit to make a 4l80 into a six speed but unfortunately you have to use their controller as well and the kit as a whole is $$$$$$

venomhp

iTrader: (13)

Yea Ive seen that kit, not really worth the extra dough IMO I just kinda like the cool factor of having the newer gen IV engine tranny combo I know it may be dumb but maybe you understand lol.

350SS

iTrader: (38)

I agree just wish there was more aftermarket support which there will be eventually. I like the 4l80 to six speed idea since less tunnel mods required...just wish there was a way to make it happen with the stock gm computer

parish8

iTrader: (6)

i have had both and at various hp levels. it is hard to see an advantage to the 6speed auto. is more shifting really a good thing. the 1st gear in the 6l80e is so short i ended up programing it out completely but that was at a higher hp level.

stock vs stock the 4l80e will hold a lot more power
built vs built the 4l80e will hold a lot more power
shifts are good with both trannys up to 500hp. above that getting thre 6l80e to shift properly is not easy. most of the shifts are 2 event shifts. one gear has to release while another comes on. it has to be timed just right or you get slip or bind. you have none of that with the 4l80e.

4l80e is cheap. $600 or less around here for a used one.

that being said at 450rwh the 6l80e would work fine if thats what you want.

venomhp

iTrader: (13)

Good info, thanks parish I think that may have been the deal maker

thedude707

I'm sorry i know this post is from along time ago but i cant't help it, If you don't know what your talking about please don't give FALSE information. The 6L80E can handle much higher HP numbers than you think. The 6L90E didn't come out until 2009 and before that the 80 was handling it just fine. How can they be 2 event shifts they DONT HAVE BANDS only clutches!!!!!! THE PROPER WAY TO FIX THE SHORT GEARING OF THIS TRANSMISSION WELL ACTUALLY ONLY 1ST IS TO CHANGE THE REAR END GEARS JUST LIKE THEY DID IN THE NEW CTS-V. Comes with 640HP stock!!!! and 3.23 gears. I hope this helps somebody!!!!!

parish8

iTrader: (6)

Stevotivo12

Had these same thoughts myself. Having a super short first gear allows you more flexibility in tuning the vehicle ultimately. You would want a 6th gear for economy purposes primarily, but the 6L80e’s gear spread also makes it suitable for a wide range of builds and goals.

Has anyone on here done a 6L/LS into a 4th gen F body? Could care less if it was a Camaro or Firebird but would love to hear how much goes into adapting the two wiring harnesses or if it’s just worth it to pony up for one of those fancy speartech harness adapters. The fact that the newer transmission operates off a can-bus system is the primary concern