Thread: O/D Tranny for a BBC

Tweet

Hello I'm new here and at least for now I joined because I figured this might be the best place to as this question. I am rebuilding a 1973 IH Scout II, my plan is to put a 454 in it, it's no problem to put a TH400 behind the 454 but I'd like something with an overdrive! Here is the kicker though I don't want any computers in the scout!!! Do I have any options other then adding an O/D unit to a TH 400?

Thanks in advance

After pricing out 700R4's, 200R4's and stand alone kits for 4l80's I ended up a GV unit behind a TH400. I picked up a 400 from a friend, had another go thru it with a Jakes race kit and added an ebay GV unit. Including a good converter I have less then then 2300 into the whole thing and it is bullit proof. It's going behind a 509 in my Astro.
Mark

Apparently your not keeping the Scout four wheel drive? If you're going 2WD then Mark's suggestion of a GearVendors OD is a great idea!

If you're wanting a stand alone OD tranny and your concern is not wanting/having a full blown ECU there are options for stand alone electronic controllers that you can use. Yes, they're a "computer", but dedicated to the tranny without a bunch of details to worry with. A comparison of some offered - Testing the Latest Transmission Controllers - Car Craft Magazine

No I am planning on keeping it 4wd and using a th400 out of a 4wd truck. An OD would be a benefit but could live with out it.

Originally Posted by Broncs

No I am planning on keeping it 4wd and using a th400 out of a 4wd truck. An OD would be a benefit but could live with out it.

A Gear Vendors unit is not an option then, as it would have to fit between the tranny and the transfer case. Seems that your best bet would be to look for a 700R4 out of one of the GM 4WD units built. Lots of them to choose from, then you could pick up an aftermarket controller for the electronics.

Ok that was something I thought about at first but everything I read said that the 700r4 wouldn't/ won't last behind a BB

That is not true. A whole lot of it depends on what kind of HP the big block is pulling. A stock 700R4 should be good for a bit over 400 HP and can be modified to hold up to well over 600+. You can go to a parts yard like Pull-A-Part and buy a complete transmission/transfer case assembly from a Chevy 4X4 for around $200. It would bolt to the engine without the hassles of adapters and such. You can buy a kit that will let you operate a 700R4 without the use of a computer. You can even buy a "Built" 700R4 for around $1200 that is already set up for as much as you can throw at it, plug and play.
Most of it is going to be determined by your ability and desire to get it done. Is there even room for a big block in a Scout without major modifications? Then again, modifications are no big deal, it is all mind of matter. If you don't mind, it don't matter.

Originally Posted by Hurst01

That is not true. A whole lot of it depends on what kind of HP the big block is pulling. A stock 700R4 should be good for a bit over 400 HP and can be modified to hold up to well over 600+. You can go to a parts yard like Pull-A-Part and buy a complete transmission/transfer case assembly from a Chevy 4X4 for around $200. It would bolt to the engine without the hassles of adapters and such. You can buy a kit that will let you operate a 700R4 without the use of a computer. You can even buy a "Built" 700R4 for around $1200 that is already set up for as much as you can throw at it, plug and play.
Most of it is going to be determined by your ability and desire to get it done. Is there even room for a big block in a Scout without major modifications? Then again, modifications are no big deal, it is all mind of matter. If you don't mind, it don't matter.

I disagree. Every weak link you fix opens the next weak link in line to contend with.

You can even get the 300M billet shafts, then you have to worry about the input drum. Then you can get the new Sonnax drum with the bolt on retainer, but it is still a cast aluminum drum. We have built 100s of 700s and 4L6X transmissions and they flat out don't last. So in the end you will have at minimum 1500 in just parts in a 700 without labor or a converter and you are rolling the dice.



Now the way I would go is a 4L80E and have just a small amount more than a top of the line 700 and it will live just fine behind a 1000HP+ Big block.