Corvette TH700R4 Trans-Pack Upgrade
DO NOT go with a shift kit for the 700R4.. it will damage it. These are the "GM" parts you can get to make that tranny a real banger.
the line pressure valve that i got  was a .470 now you can get a .490 or .500 of course the higher the numbers the higher the line pressure and the harder the shifts.... just to let you know.. before i installed this package it would never and not even close, chirp on the 1-2 shift. now its easy to do any time i want to.. i dont know if i told you, but my tranny had a 6cly servo in it.. and thats why i had such soft shifts.. i went with the .470 cause i didnt want to kill myself with the shifts.. you might want to go with the .490 ask the guy when you ask about these part #'s..
should be around $55
get someone to install them, I tried myself, and let me save you the aggravation. I am taking the car tomorrow to have these parts installed.. I have been quoted at $90 for everything including seals and fluid. these are the GM parts for the Corvette Trans.. they will FIRM up your shifts, and raise your shift points.. ***Without*** Damaging your tranny.. I have done a lot of investigating on what is the best for our trans.. and this is the best.. as for the rear.. go with a set of 3.73's go higher if you don't drive too much, maybe 4.10, but if you want reasonable gas mileage go with the 3.73's.
from what I understand there is a coupling in the 700r4 that is weak and some of the shiftkits that are out there cause an enormous amount of strain on that coupling wearing it out and eventually breaking it. and I have heard this from more than one person, but that's not to say that "all" the shift kits are bad for the 700R4 its just better to do what the manufacturer does, and that is replace the servo with a larger one, and raise the line pressure.. this takes a lot of the strain off the coupling and puts it more on the plates..
I just got these pieces installed today, and what I can tell you is that it is awesome to say the least. I have driven in a car with a shift kit and now I have driven in a car with the new servo and pressure regulator, they are surprising two different sensations... the car with the kit just banged into gear at any throttle, but the servo is easy on the low power, and breaks loose in 2nd and chirps 3rd.. it just feels better. and the trans place I took it to install it said I was smart for doing this instead of going with a shiftkit.