When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I'm just getting started with the transformation for my 89' Iroc, and although the 5.7 and 700R4 have served the car well, they are just a bit tired and a bit sluggish compared to even modest modern cars. The solution - a new heart. To go with it's new heart, I want modern brakes, suspension, and transmission.
To the subject of this thread, I want to use the 8L90, but it looks quite large. I can't seem to find the dimensions of it online anywhere, so it's a bit tricky trying to figure out just how much room needs to made to make it fit. A lot of this work isn't just a bit beyond my expertise, it's mostly just beyond my available space and tools, so a shop will be doing the actual installation, but they haven't put this transmission in anything nor has anyone else I can find.
I really intend to use the car as a daily driver, so as many gears in an automatic as possible is the goal. If the 8 speed doesn't work, then the 6 speed auto is the next candidate, although it's still on the large side. Anyone have any experience or have any of the dimensions of these units?
The 6L90 needs clearancing. The 8L90 is supposed to fit where the 6L90 does. And the 10L90 is supposed to fit where they do too.
You could test fit it, ease it into place, and add clearance where it rubs. Sometimes, a trans. that almost fits will self clear, and shimming under the trans. mount helps accelerate the process. Other people will tell you a whole new floor needs put in after yours is cut out! lol The 90s will need most room where the rear tail housing bolts on, and forward of that for several inches to a foot.
Since you're farming out the work, get comfortable with what they tell you with what they'll do to expand the floor (cut, weld in new strips of metal, shaping along the way) or if you aren't comfortable, move to another. Way more important than the housing(s) is driveline clearance, and a fidget spinner, I mean fixed yoke (all cars) is larger diameter than a slip yoke, which were used on some trucks.
I appreciate it, so it sounds like it can work. I don't mind them doing what they need to do to make room, so long as I can retain factory accessories and they do a professional job of it. Put carpet back over it, and I'm sure it'll look good. The goal is to retain as much factory appearance as possible, at least at first glance.
I appreciate it, so it sounds like it can work. I don't mind them doing what they need to do to make room, so long as I can retain factory accessories and they do a professional job of it. Put carpet back over it, and I'm sure it'll look good. The goal is to retain as much factory appearance as possible, at least at first glance.
I am very interested in how this goes for you I would love to put one of these trans in my 83 If you have any chances to take pictures or are willing to tell us what a shop charged and what all it entailed I would appreciate it
I am very interested in how this goes for you I would love to put one of these trans in my 83 If you have any chances to take pictures or are willing to tell us what a shop charged and what all it entailed I would appreciate it
Oh, I promise to keep everyone up to date on how it goes. The drivetrain will be at the tail end of the project, brakes and suspension come first. This isn't necessarily an all at once bid.
Hi I thinking of the same 8L90 in my Camaro.
GM PerformanceMotor selling the 8L90 for just $4600 https://www.gmperformancemotor.com/parts/19356329.html but it needs the engine controller (P/N 19355167)
It costs $ 7041 with harness and controller.
I`m thinking...
I have a 82 Camaro (with lots of mods ) a zz4 with Holley Stealth Ram HP efi.
I think it have been possible to "implement" the engine controller (P/N 19355167) to the holley EFI ?
A strange marriage but I like the strange an unusual
And a 8 speed transmission in that car would be great !
My concerns are: Have I modify the tunnel to get clearance?
I have owned this car for 27 1/2 years so looking forward to give it a good 30 anniversary gift
I believe it's not an engine controller, it's the trans controller (TCM). 8L90 I'm not sure about, but I know there are plug and play kits for most other GM modern transmissions for hot rodders and retro fitters. Prob 8L80 and 8L90 too. 8L80 holds ~500hp, and 8L90 clost to 700. 8L80 might be a better option. The TCM would need inputs from the car harness, or maybe even new sensors, but from what I have read GM makes an easy package to retrofit, relatively speaking.
That being said, like you know, there will be mods to the tunnel as well to make it fit. prob crossmember, driveshaft also.
It's a major undertaking. But I have the 8L80 in my 2017 SS and it's fun as hell. It would make any third gen a whole other animal. I still like my clunky 700R4 in the old girl, just rebuilt and I'm not pushing any real power so hopefully it outlives me.
06-20-2017, 09:07 PM
I thinking of the same 
