8L90 behind a BBC?

Transmission to Rear-end

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John Ross
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8L90 behind a BBC?

Post by John Ross » Sat May 13, 2017 4:12 pm

Does anyone have experience with this?

JR

pdq67
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Re: 8L90 behind a BBC?

Post by pdq67 » Thu May 25, 2017 6:16 am

No!

What do you want to know?

Will one hold up to an 800hp/800t 632" BBC??

Let's get real guys so come back and talk to the man!!

pdq67

John Ross
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Re: 8L90 behind a BBC?

Post by John Ross » Sat May 27, 2017 9:05 am

805HP/795TQ 572" motor, actually...

Doing further research, it looks like nobody seems serious about trying to make this unit live with high output modded motors. I had hoped that the high factory torque rating of 635 ft-lbs, and its use in both the supercharged Corvette and in trucks designed for towing heavy loads, would mean it was a good candidate.

The electronic trickery required to make the 8L90 function in both those applications may mean it's a no-go for a carbed mountain motor. Same with the 6L80.

It looks like the 4L80 is the OD auto trans of choice for my application, which is a mid-engine, Trophy-Truck wannabe playtoy. That's why I wanted the wide spread of gears...

JR

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Re: 8L90 behind a BBC?

Post by PackardV8 » Sat May 27, 2017 11:21 am

Just for our education, can you show us a photo or a link to a similar "805hp BBC mid-engine, Trophy-Truck wannabe playtoy"? Not something with which I'm familiar.
Jack Vines
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John Ross
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Re: 8L90 behind a BBC?

Post by John Ross » Sat May 27, 2017 12:11 pm

The Superlite MOAB. Originally designed to use a late model Corvette rear-mounted trans/diff and an LS motor, the Corvette diff didn't allow low enough gears for the 37"-40" tires the vehicle uses. Redline in first gear would be 90 MPH or so, and there was some question about whether or not the Corvette diff would be strong enough for serious offroad use.

RPM Transmissions in Anderson, Indiana has come up with a package to bolt a 9" Ford directly to a 4L80 for this application, so gears as deep as 6.50:1 can be used by the rock crawlers. Here's the page that shows it--scroll to the very bottom: http://www.rpmtransmissions.com/page9.html

Superlite Cars and Race Car Replicas (RCR) are run by my friend Fran Hall, who makes great stuff. I have three of his creations so far. He says no problem setting up the MOAB for a BBC.

I turn 60 in a month. I'm getting rid of the last of my bikes, and thought a go-fast off-roader would be a fun replacement. See it here: http://www.superlitecars.com/moab/

JR

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Re: 8L90 behind a BBC?

Post by pdq67 » Sat May 27, 2017 3:15 pm

As far as I see it, the still-born 12-bolt 2-speed type rear end that Ford tried to make back in 1969 should have been a real winner, but,,,,

The Cougar 2-speed rear end here is all...

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