What motor will the 4r70w mount to? My C6 (460) is much longer than my C4 and FMX. A trans X member is usually required, unless you can fab yours.

If you are possibly looking for a good rear transmission mount for a 4R70W, Joe Persad at premiergenerator@gmail.com sells a good one. I used his on my 4R70W install to my 351W in my 68.
Check out the picture here: http://fyi.boardhost.com/viewtopic.php?id=4863

Wading through the various founded and unfounded data, it appears that the limiting factor on the V6 converter is the lock-up clutch torque capacity.  Apparently they are good to approximately 350 ft-lbs.  Above that, slip and excessive heat can take out the converter and the trans.  However, with some relatively easy programming in the Baumann unit, you can have the trans "unlock" under certain operating conditions which should prevent/limit this.  With a healthy 5.0, you should be OK.  A stout 351 Windsor or Cleveland would do better with another TC.  I am running a TC from a 5.4 truck in my 1970 F-250 behind the 390 and soon to be 445.  It is considered a low-stall and also has a lower torque multiplication factor of 1.1 which should allow the 4R to survive.  The hot setup is supposed to be the Mercury Marauder TC with a little higher stall but it may take a small bolt-pattern flex plate.  The 3.8 V6 and the 4.6 V8 are don't make gobs of low-end torque like a good Windsor 5.0 so they have higher stall speeds that you may not really need. 

All that said Bob, if you decide you want to start with a fresh unit with a pick up stall speeds, my neighbor gets good units for about $150 exchange in Denver.  90% chance that your used V6 converter will work fine in your car.  For me, I seem to always fall into that 10% category.  Murphy and I are close friends.

Internally, the V6 trans is supposed to have one less clutch than the 4.6 cars.   Looks like properly sourced parts cost about $20 bucks but you'll have to open it up to install.  Not a huge ordeal.  For a 5.0, it may be fine.  For a 351, I'd probably do the upgrade.  All the other components are essentially the same.  

My info so far the 3.8 4r70w would most likely stand up to the 351 w with its 400 ft pounds of torque . But the stock convertor may be the weak point, When I started this project way back when Aod conversion were just starting so I went back to the stock transmission a C-6 . Now that I can see a completion to this , Now thinking about driving it and with 3.55 rear gears it will be cranking a highway speeds

Bullet Bob wrote:

Ron68 wrote:

If you are possibly looking for a good rear transmission mount for a 4R70W, Joe Persad at premiergenerator@gmail.com sells a good one. I used his on my 4R70W install to my 351W in my 68.
Check out the picture here: http://fyi.boardhost.com/viewtopic.php?id=4863

Hi Ron, when are we gonna see you again at a Bash? 
And, what torque converter are you running in your 68?  I've been told that you need to upgrade from the V6 to a V8 TC...and then I've heard that you really don't.

I have an 03 trans plus the 94 computer that I plan to slip into the Heap one of these winters and I don't want to buy a different TC unless I really have to.

Thanks, hope to see you again some day.

BB

The transmission I have in my 68 is from a 1998 F-150 4.2L. I have a V8 stall converter in the transmission. As far as me making it to a bash - They all seem to be out of range for me - always in the deep south or east of the Mississippi. We never seem to have any on the west coast (except for yours in Colorado, which I couldn't make) I have made two in Texas and one in Montana - but maybe when I pull the plug at work, I'll have more time to make one of those far away bashes. It's a very long way to drive my 68 to any of the bashes of late from  Seattle. Once retired, I can maybe take advantage of those travel benefits I have earned from 35 years of twisting wrenches on Alaska Airlines aircraft. Until then, I'll just have to live vicariously by looking at all the photos posted.....