If the 6l80 was bulletproof I would still go to the 4l80. The big thing is control and the first gear in the 6l80 is just to must. With my engine its hard to hook it up.

 

And yes the 4l80 is a stronger trans over all.

 

You could always add a gear vendors if you need more over drive.

 

Rick, that right I would get 25mpg..

 

Much more so than the 6L80E, yes. From the gear ratios to the powerflow, it is much more performance oriented than a 6L80E.

 

the 6l80 can handle 800rwhp is calibrated right.

 

I am a professional GM racing transmission builder, so I know what they all can and can't do

Sure but you need to find a tuner who knows what he's doing first. No matter how well you build it, if the tune isn't right it's history. If I had a dollar for every call I got about a built 6L80E that was blown up on the dyno or on the first or second pass and now they were coming to me for a 4L80E, I'd have over $100 extra dollars.

And really, 800 is good and respectable, but there are a LOOOOTTT of guys making a lot more power than that. Mark here is just one example of thousands. A 6L80E isn't going to cut it.

I'll humor you though. Let's say the 6L80E and the 4L80E could both hold the same amount of power. Obviously there would be major design differences in the 6L80E if that were the case, but let's say they're still the same design-wise. You are still going to run slower times than you would with a 4L80E, and you still have an inferior power flow design. If you're looking for some better gas mileage, I'll tip my hat to the 6L80E, but for high power racing, this will not be the transmission that will overtake the 4L80E.

 

Oh yes! My stock 6l80e took a 2yr beating from 600-800rwhp in my Denali and last I heard it still is!

The 4L80E is the better trans no doubt about it, BUT the 6L80Es I keep seeing are lasting and lasting more and more maybe i had a factory freak 6l80e that hasn't burnt out till this day again from 600rwhp to 800rwhp new onwer still doing hard launches and stuff. Now in the vette and 5th gen world they are holding for 10sec 9sec 1/4 mile times stock. built ones 9sec to 8sec passes. But yes I agree the 4l80e is better than the 6l80e but they sure last!

 

The 6L80 is good in the 600rwhp. But I was slipping the hell out of dot at the track with that
4.03 first. The 2.48 will be easier to manage and the shifting over power just better.

 

Back to building. Ordered my AMS 500 boost controller and the push to connect line and fitting. Trans is going out soon so I hope next week Xmas will come and I can get busy
put the Beast back together. Im ready to run it and so more dyno testing!!!