If I build a 383 stroker putting about 450 torque on the ground i am obviously going to have problems with the 700r4 my question is is it worth buying a build kit for one and building the 700r4 or should I just junk it and buy something else?

Its really up to you. 700r4 have a huge affter market, and they have been built to handle a ton of power. But the problem is that that will cost alot of money.
another option is to find a good used TH400, i heard of those lasting awhile in stock form behind 450 plus HP motors. but then you also loose an overdrive if you go to a TH400.

You also have to consider the cost of new crossmembers with the proper torque arm mounts for a TH400 or a TH350 into the "cost" equation. Search Jegs or Summit or UMI or Spohn for crossmember prices as TH400 and TH350 will not simply bolt in our cars.

I found a local tranny shop guy that rebuilds on the side at home and I got a really nice stout rebuild on my 700R4 for only $500! You just have to do some inquiring with the guys in the shops that have dirty hands, and not the khaki-wearing counter jerks.

He definately got a Point There. and i agree with talking to the real hard workin' types rather than the manager types. those guys at the very least can give you good advice.

450tq is nothing. ill be putting out more than that with my 383 i just built(in sig). if you upgrade the 700r4 right they can handle 700hp no problem(also in sig)... mine can handle 675+hp. the th400 should only be used if u NEED A REALLY STRONG TRANS! like your car is faster than 9s in the 1/4.

PPl dont realize that the TH400 is a bunch heavier than the 700r4, the TH400 also has heavier internals that take more HP to spin. a heavier trans, with heavier spinning internals means u have a slower car with nothing else changed. ppl usually swap th400s for 200r4s(which can be built to handle 1000+hp) and they area actually faster in the 1/4. not to mention the addition of overdrive etc. IM SICK OF PPL saying the 700r4 is a weak trans...the 700r4 in stock condition is a weak trans bc it was built to handle the max of 245hp. you put 500$ in a rebuild kit that will change everything in the trans and make it handle 600-700hp and then u spend 200-600$ on a converter and you still be cheaper than a Th400 build/swap.

gona help u out a bit here
call DANA heres his site.
BUY THIS KIT! but talk to him and order it bc he will match it to your engine/trans/rear gear/vehicle weight etc. this guy knows his SHlT! and he wont screw u over and hell spend all the time u need on the phone with u.
depending on the year of the trans and what power u will make choose a kit
https://www.700r4l60e.com/store/home.php?cat=19
the 700r4 first gear is 3.06 which is the steepest gear in all the auto transmissions... it will get u out of the hole in NO TIME! the 1-2 large gap shift will not be a problem if your making enough power

i would not trust a 500$ rebuild. a good upgrade rebuild kit without servos/boost valves will cost you at least a minimum of like 300$ depending on the brand. this brings me to brands that suck... B&M, TCI, and most of your online companies like monster etc.
so figure u get a cheap moderatly good rebuild kit for 300$, then add servos (at least upgrade to a corvette servo) thats like 20-40$. billets like mine that are the largest will run u like 200$. then add boost valves about 30-40$ there. then figure a shift kit (arent included in real good rebuild kits) i only trust TRANSGO.... thats like 100$. thats already more than the 500$ for the rebuild for a "stout" rebuild. stout for them is a stock rebuild with a shift kit and maybe a servo. this guy still needs to make money for the build bc it will take like 6hrs to rebuild one if your FAST!

im just saying dont screw yourself on this one. get a real kit from DANA who works out all the problems for u. and his kits are STRONG! no ones trans breaks who buys from him. his "heavy duty' kits are better than the B&M kits and TCI etc...