My friend that runs a dyno/speed shop uses TH400 and 4L80E most of the time Or a Glide.
I have thought OD many times and the 700R4 does not survive behind a lot of my friends rides so that is a no go.
You can add roller bearings at the thrust bearing area's and eliminate some of the friction in the 4L80.

I think Jakes does that or can.

 

In short...no...a built 4L80e is your only option...When you're making 1000HP, who cares about robbing 20-30 extra HP in a cruiser?

Andrew

 

Keep the TH400 and add a Gear Vendor unit… :yes:

Claude.

 

I've thought about this allot. Was hoping for a cheaper option, once can dream A company did a write up on the 6L90E out of a 1 ton truck saying they could handle about 800FTLBS of TQ so it got me thinking...after some reading im not so sure I believe them.

Im thinking the Gear Vendor is the best option as my TH400 is already built for 1000HP and has all the goodies.

 

If you're going to have 900-1000 hp just keep the 400 & put a 3.08 gear in it.

 

I wish I had done this. I was talked into the 700r4, I hate the gearing in it. Its hard to shift into second gear before the engine is past the red line. I was going to change the rear gear from 3.31 to 3.08s and have a turbo400 built, the trans guy talked me into changing to a 3.73 and 700r4, I just don't like it but I will probably live with it.

 

I do have a 700R4 in my car and absolutely love it. I would never go back to my old TH400... I had to go from 3:08 rear gears to 3:73. Yes there is a big rpm drop from 1st to 2nd gear with the 700R4 but a healthy big block engine with lots of torque shouldn't have any problem to overcome this..:yes:

Claude.

 

FWIW.. went to a locally built 700r4 about 4 years ago for my 67 ss 496. my 496 motor made 627 ft/lb on the dyno. the trans has been real good so far. I run 3.42 rear gear. rear tires are 28"od. (275-60r-15). the 3.08 low gear of the trans make the car feel like 4.11's are in the back when in low gear. on the highway the tach reads about 2300 rpm doing 65-70mph. true the 1-2 shift is a bit funky but as previous poster replied - you don't care with a healthy bbc. Like it also because there is no electronic crap to deal with other than a late model brake switch to deactivate the 4th gear solenoid. use a lokar tv cable that is very adjustable as well. truly doubt the trans will survive behind 1,000 hp but don't know for sure if properly built...

 

another vote for the 400 and 308 gear here

 

If someone wants some 3:08's let me know…

Claude.

 

My vehicle had a gear vendor unit when I purchased it. Changed 4.11 to 3.42 since daily driver. You also have to change the oil in the GV every 5,000 miles.