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4L80 Upgrade

shortydog

shortydog

Full Member
Joined
Mar 3, 2008
Messages
316
The stock 4L70 finally gave out after years of abuse. The transmission will be upgraded to a 4L80 with billet internals. A PI 3800 stall will be added. The flywheel had a small crack, so it will be replaced with a  Circle D flexplate.



 
You should expect to loose power and response going from the 4l60e to the 4l80e transmission. Much stronger transmission but not nearly as efficient. I have been told to expect 2-3 mpg loss due to the transmission. However if you are going to a bigger engine or adding significant power it is hard to beat a 4l80e.

Rodney
 
The engine is a 408 but, plans are to add a turbo later on. The 4L80 is suppose to handle 1000 HP but, I would like to be around 800 to the wheels. My gears are 4.56 so that will help with the 1st gear of the 4L80.
 
Gonna be a very cool build. Wouldn't mind getting and 80e in mine eventually after I go through a few built 65e's. Keep the pictures coming!
Cheers
 
Lol I've been running the 408 for about 3 years already I think.  But I'll keep posting information as I continue upgrading slowly. The original 4L70 handled a good beating and I was surprised it lastes this long.
 
shortydog  what amount of horsepower and torque are you running with that 408?
 
It made 449 HP and 436 TQ on the dyno. This is using the stock L92 heads and intake. Stock fuel injectors and fuel pump. So there's plenty of room for improvement.
 
I assume that is at the crank...? Impressive numbers. With this 80e I hope to see a new thread in the future of some boost going into it  :D
 
No the numbers are at the wheels not crank. That is the plan to add some boost later on  ;D
 
Those L92 heads will work with a LSA.  (y)
 
Now you have to figure out how to control it, I can program the ECM on my Gen 2 to do it. Your Gen 1 will be a little harder. What's the compression ratio on yours hopefully it's under 10 to 1 limit it to 5 PSI if it's not.

LSAs are only 9 to 1
 
Correct me if I am wrong, the 408 is a stroked 376ci (6.2L) correct? Those are some impressive rw numbers. What gears are you running at the back?
 
Lots of torque coming out that back end haha.  Gonna be sweet with this new tranny in it. Are you doing the work yourself?
 
Due to work I'm not doing the work myself. It's been done at a friends shop. The torque gets the truck moving pretty quick  (y)
 
Those 408s are such a BA motor, I can't imagine it with 4.56 gears. It must run like a scald rat.
 
I  had 4.10 gears before but the 4.56 feel a whole lot better for me. I'm running 24 inch wheels so that helps on the highway.
 
Wow. Now I have to imagine it with intake, injectors and boost. Literally a rocket haha. Do you have a video of this beast running the way it currently is set up?
 
Thanks and yes I have a couple of videos on YouTube.  

https://youtu.be/bH01Rfk3qbU

https://youtu.be/AerjRIFXrPw

https://youtu.be/VzmXiGB3ghE
 
I'm not a fan of street racing, have you ever taken it to the track. I just wonder what type of times would you run.
 
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