automatic. siftless or not?

Valid point however letting it shift by itself is a slow shift which heats up the tranny fluid a lot..  Ah well maybe that will ruin the transmission and then I can swap the manual in?
Nah, I don't want to drive that much!

You're trying too hard. Turn your A/C condensor into a transmission cooler, and put it in Drive. That's what we did with the Jaggernaut and it worked just fine. If you're wanting a higher shift point, swap in an adjustable vacuum modulator and you can tune it at the track to shift where you want.

The two guys how can't drive stick might be faster to fix!!

Oh you know the A/C condensor trick too? One of the minor little tricks I'll use is put the Cooler in the spot on the firewall where the A/C usually goes.. Then run heater duct work back to the  rear license plate.  That will  do 5 things, 1. Do  a nice job of cooling the transmssion because of air flow through the cooler.  2. lower under hood temps because of air movement 3. dump the air out in a place that will actually increase air flow due to low pressure area. 4 provide fill air in an area that is normally turbulant because of vacum. 5 which will decrease drag.
Both the oil cooler and the transcooler will be fire wall mounted.It will be legal since the metal ductwork used will provide the required firewall.
          You had me there.. I had to go down into my shop and double check.On the earlier transmission like I'll be using there isn't a vacum modulator. It uses the HD truck valve body.. and spring tension alone determines shift points.. (to adjust shift point trans pan has to be dropped, valve body removed,  spring replaced with heavier spring and reverse the process.   Since the HD truck spring is as heavy a spring as is available custom wound spring must be used and there is no data that will tell me what tension is required to shift at 6500 RPM..  So it's strictly trial and error.. (no shimming the spring won't work either)
    On the Jag V12 the cooling system is not well thought out..The flaw is that it's as easy for water from the front cylinders to pump water back into the return rail, as for the back cylinders. The total volume of water flow from the heads is greater than the amount of water flowing.. thus the front cylinders tend to get cooling water several times while the real cylinders tend to have stagnant  (overheated) water. If the pick up point from the the end is at the rear water will flow far more evenly and the back cylinders won't stagnant..    To achieve that simply reverse the water outlets. Left front to right rear, Right front to left rear and visa versa..   Now just collect the water in a header tank and run it forward into the radiator.. 
  That will drop the water temps by more than 80 degrees C
No more blown head gaskets!  Couldn't do it on street engine,, a race engine once pollution stuff is removed and battery relocated etc.. has plenty of room on the fire wall for the mods mentioned..

3rd. earlier transmissions are 3 speeds.,

Heh, heh,  You might have something there.. but they are friends and we won't stand a snowballs chance in hell of winning* so it really doesn't matter..
* too many pit stops for fuel.. most cars can run about 2 hours per tankful, the thirsty Jag will average about 40 minutes.. If I switch to ethanol like I want to that means in a 24 hour race I could be in the pits 100 times for fuel..

yes the TH400 is stout but it's designed for far lower RPM operation.. It takes the heavy duty truck valve body to endure the rpm the V12 operates at..
   I suspect if you tried to race a bone stock TH400 in a Caddy the High RPM's would quickly do it in.. The lifters on a 500 CuIn Caddy would start to pump up and prevent the engine from turning anywhere near the RPM the Jagaur is capable of..
That plus the torque converter is such a massively heavy beast, I wonder what it's RPM limit is as well. 
Guess I'm gonna see. 
ON a differant issue,, is the tranny in a 500 CuIn Eldorado the same turbo 400 just modified for  front wheel drive? 
I can see my duel engine car now.. a pair of V12's in an Eldorado..

24 pistons singing a song.. Now that would be  properly insane!   Hmm I even know where a rusty Eldorado is!!!

In our J30 I moved the condenser and blower assembly to the trunk.  I run the blower full bore, it removes a lot of heat and the trans is a survivor.

the 928 has an automatic...buts a Mercedes 722.3 unit...the nice part about those is you disconnect the bowden (throttle) cable and the kickdown switch...then it only shifts by the lever...and shift firmness-pressure is controlled by the vac modulator....works really well on the 928...just install a HUGE cooler and you'll be fine

We did NOT like running the automatic in auto mode...(with the bowden and kickdown connected)...it would spin past redline and kickdown in odd spots (like mid corner)...its better using it like a clutchless manual.....

Now do the math using ethanol (1/2 the mileage)20% more power
  At $3.00 a gallon that's504X3=  $1512.00
Ethanol is only$1.00 a gallon but twice as much needed so fuel costs would then be $1008. a savings of over $500.00
  Early Jag V12's got 8-11 MPG in testing with one testor reporting 4 MPG on a tank of mainly high speed and near racing conditions..
  (wanted to confrm 150 MPH top speed). 
Later HE's got 16-17 MPG but they tend to run extremely lean, overheat, and blow head gaskets under racing conditions..