How did you adjust the TV cable? It is a quite sensitive adjustment, and
as
little as 1/8" makes quite a difference. Mine took quite a while to get
right. A good starting point is to open the throttle all the way and
then
adjust all the slack out of the cable. This is usually too much tension
on
the cable, but it is a safe starting point.

Also, don't get me wrong. The 700R can take a lot of punishment, but it
was
never designed in stock form for something with the power of a 426 Hemi.
The
most powerful engine put in front of a stock 700R was the 454 found in
the
84 and newer trucks. I believe the SS454 would have been the most
powerful
one, but I have no idea of the HP or torque that engine puts out. It's
not
even in the same class as a stock street Hemi, let alone a Hemi that has
been modified.

If the trans is slipping in all gears, then the pump is probably not
doing
it's job, or the TV cable still isn't right. The older 700R pumps were
prone
to cracking the ring that retains the pump vanes. If this happens, then
your
pump will lose most of its pressure, which in turn will cause less apply
pressure to the clutches and band.

If it is slipping in 2nd and 4th, then the band is gone or the apply
servo
isn't applying enough pressure to hold it. This could be because of a
bad
servo seal, or just the fact that you are overpowering it. There are
aftermarket servos available, in addition to the Vette one. The nice
thing
here is that they can be changed from the outside of the case, as long
as
you can access the servo cover. But like I said, the bigger the piston
here,
the slower it will shift into both 2nd and 4th gears.

If it is slipping in 3rd and 4th only, then it is more than likely the
3-4
clutch pack, or the apply piston seal. The 3-4 clutch failure is quite
common due to the lack of cooling of these clutches. This is because of
the
transmission design. The clutches are buried inside everything else and
are
the last thing to get lube, even though they are the ones doing the high
load work. The mods for the 3-4 clutch involve drilling extra oiling
holes
in the clutch drum, as well as upgrading to 2 extra clutch plates and
steels
in the clutch pack.

BTW, whatever that Hemi is in with 4.56 gears and a 3.06 first gear has
got
to have one hell of a holeshot. I hope your friend gets this sorted out.

Also one other note. Painless makes a wiring kit for the converter
lockup on
non computer vehicles with this transmission. It is basically a new
solenoid
that goes in the valve body, along with a brake switch and a vacuum
switch.
The kit allows the converter to lockup in 4th gear only, and it
automatically unlocks when the vacuum drops below 12" (I believe) and
the
brake pedal is not depressed. This is the kit I used in my S10 and it
works
great.

Chris