So I need to put something behind a fairly serious turbocharged small block that will see _a lot_ of dragstrip passes, but also some street abuse and maybe even some road course/autox... I have a 4L80e for it, but I keep wondering if I should reconsider something simpler/lighter.

How strong can a TH700r4/4L60 be built for reasonable money? I've ended up with the no or really slow 1-2 shift multiple times with much less engine in front of the tranny, and have found that some valve body work makes that better, but once you kill it once the drum band never works the same, and even a full rebuild only has limited life at that point, of course that was a few years back, I'm wondering if better parts or procedures exist for them now?

 

They can be built to take a lot these days, as I have had many in the 10's and some in the 9's over the years. But since you have the 4L80E, it would be easy to make this hold up to 750 - 800 horsepower without any speacial hard parts. What year do you have?

 

I have an '87 TH700r4 (though they're easy enough to find for cheap, I know it's the weird one that is different then the earlier and later ones, it needs a rebuild, only has first gear, but it's got a transgo kit in it, big TV bushing, piston...), and I think it's a '94 or 95 4L80e.

I started going through the 4L80e, have cleaned it up (it had less than 30K miles on it anyway), did all the transgo stuff to the valvebody but I'm somewhat nervous about the pump mods since I've never had one apart. I also have a PI 3 disk clutch converter for it, TCI control box... Transgo claims 950lb-ft with no hard parts changes...

 

It depends on what year you have. Yours is not the one. You will need to add a 34 element sprag and the HD snap ring that holds the 2nd gear clutches, and the HD springs for the direct drum. These all come in the kit. Depending on what torque converter you are using, will determine the hole sizes in the separator plate.