I just purchased a working 700R4 core, and will start rebuilding it pretty soon. I already decided to buy the kevlar band and clutches, firmer shifting servos and several other performance pieces, but I need to know what the main weak points of the 700R4 are, I plan on making some major power with this car. If anyone could shed any light on this it would be greatly appreciated. Please no TH350 or 400 suggestions, I do want overdrive. Thanks.

Overall, its a good trans, especially with the mods you listed. The main weak spot is OD. But even then, the rule is just never tow in OD.

Towing? In a firebird? Nice. Anyway, third gear seems to be the trouble spot. Everyone seems to have a hard time getting a firm 2-3 shift due to some much needed separator plate/servo/boostvalve problems inherent to the 700r4. Make sure tho get the 3-4 clutch pack with the extra clutches (7 or 8 I think) instead of the stock 5 or so. And dont forget the B4C police 3-4 upshift valve available at most GM dealerships (I have one and I must say that you WILL kick yourself later if you dont put this in during the rebiuld) . Do a search if you dont know about it and Im sure youll find a part no. for it. Thats how I got mine.

does the transgo shift kit have something similiar to that upshift kit you are talking about in it?

Ive heard that the input and output sections of the 700 are prone to cracking under any large amounts of torque, is there any validity to this?

I dont have the transgo kit yet but I dont think it has the modified valve or sleeve for the 3-4 shift. DONT get the b&m one -it only raises the downshift to 3/4 pedal. Not a FULL throttle upshift. The part No. for the correct GM police 3-4 upshift valve is located in the technical articles section under 700r4 modifications. Its only 15 bux at the dealership so run (dont walk) and get one. If you set your TV cable a little loose to shift early at WOT you can stand on the gas w/ both feet on OD and it wont downshift. Granted, its giong to downshift if your are going relatively slow for the given gear but once you reach a certain speed there is ZERO downshifting unless you move the shifter manually. Cool huh?

Go to my website www.pro-built.net and lookup the HD or Street/Strip 700R4 rebuild kits and you will see what I do to make these units last. The 700R4 when setup correctly will hold up very well.

I got my trans rebuilt, got monster boost valve and upgraded internals and some other stuff, Ive only floored it once from a roll and when it hit third i got rubber w/ 275's on the back Guess Im just lucky. Oh and there were 6 stock clutches in my trans, I now have 8, that (i was told) will help to hold up to more power.

I just picked up the B4C kit that Recluse referred to, p/n 8673948.