ok ive got a 88 iroc z and ive broke 2 700r4 bellhousings. first time i took it to my tranny shop and they told me it probably was a fluke and they took all of my guts from that tranny and put it in another case and didnt think twice about it. which they had rebuilt the tranny just 2 months before. well here i am 5 months after the swap and it broke in the same place. so im thinking about going to a jw performance ultrabell. im wondering if the case is the problem or the engine just needing to be solid mounted to take the twist out of the drivetrain. any second guessing or ideas of things that i might need to check out or replace. just some engine info before asking. 350 TPI built im guessing its putting out around 320 hp and 400 torque. headers, LT1 injectors, chipped. and if anybodys used or uses ultra bells how is the outcome. im wondering if i need to order one or try to get mine repaired. thanks in advance. Joseph

Are you sure the bellhousing is tight against the engine and also are the dowels in place on the engine. Also is the trans mount good?? If you need another trans I got one you can have for cheap it worked ok but may need freshened up. I did a T5 swap so its out of a 92 and I am only about 50 miles from you.

the dowells are in place and the transmission shop torqued all of the tranny bolts down and the tranny mount is new, this is the second time and i think im just putting out too much torque and im going to check a few other things but im prolly going to get a ultrabell and im also going to solid mount the engine. ive got to get the twist out some how.

An ultra bell for a 4L60 would be a waste of money. - It is breaking due to either a vibration and/or a miss-alignment/bind. Any power you could possibly make with a TPI intake is not enough to be hurting the bellhousing.

I'd have the driveshaft run-out and balance checked as well as the converter balance. If you'd still like extra insurance, use a 4wd truck case; they have considerably beefier casting in the bellhousing area. They are identifiable by having 3 large bolt holes on either side for the cast aluminum converter cover and/or a large "K" cast into the top of the bellhousing on each side.

well see my tranny is built and ive paid for it once to have the guts swapped and im not doing that again for something to "hope" it fixes the problem.
an ultrabell is not going to break and its going to be cheaper than buying a 4wd case and having my guts swapped and still be under warranty.
not to mention time. this is my daily driver im not going to take chances on something that wont guarantee <a href="http://a1.interclick.com/getInPageTarget.aspx?a=53&b=12805&cid=1236187469005">

I agree with Shagwell about the TPI not being the reason that the bellhousing is breaking. I was putting down 373 ft./lbs of torque at the wheels with my old TPI 350 and never once had a problem with the bellhousing breaking.

As suggested, it does sound more like its a misalignment somewhere or a vibration. I know you said the trans mount is new, but are you using a poly trans mount by chance? I've heard of guys having a lot of vibration by using the energy susupension style mounts before, to the point their tailshafts came loose from the mount being slightly too tall. I've noticed that my poly mount has sagged slightly over the past few years of use. Just throwing that out there.

As for going with the ultra bell, I can see why you don't want to switch the guts out again after paying for that already. I say go for it. It would be a cheaper solution to try.

the bolt on bells are being used in wayyy fast cars. shouldn't be a problem. I use one in a camaro 434 stroker small block shooting 330shot running 9's at 146+ for years.
probably you are mixing stock engine mounts with a poly or similar trans mount. SEEN IT TOO MANY TIMES-BAD COMBO-BREAKS BELLS-I TRY TO TELL PEOPLE BUT THEY DON'T LISTEN. no comprendo, they deny they might actually have built a problem into the car. When in doubt pull it out.

my car is wayyy fast. it broke a 200 MPH autometer spedo
its not a slow car

would it be a smart idea to solid mount the engine to take the twist out?