Ditto on above. NO WAY a 350, no matter how worked, is going to twist/split a drive shaft. There is defective part in the mix somewhere here, or something was assembled wrong or horribly out of balance.

A 700R4 isnt going to slip from a mild cam job. All you did was install a basic RV cam......Your not even talking much more than 35 horsepower above stock. I know you think your cam is 'massive'.....but we havnt heard you mention you needed head work or special springs or needed a vac booster, so it was a 'bolt on' cam for all that is concerned.

Something else is wrong.

 

UGH, Just MAYBE the 700 r4 needed to be rebuilt. You didn't put the torque arm back in, did you?

 

ditto on the 700R4 rebuild, its a much better trans over the th350. I would say heating and welding weakened it and thats that, get a new driveshaft. You do not need anything special, but while you are at it, put in new u-joints.

 

If he didn't reattach the torque arm to the frame somehow, that would explain the torn up driveshaft. You can't go without it.

 

found a longer driveshaft with same u-jiont dimensions, cut that one down to size. simply cut it with grinder cutting wheel. now i'm making a new one, gotta shorten it a inch. But right now i'm trying to figure out why the tranny won't shift. And yes the vaccum modulator is brand new, and it has a good tight fit for the hose. And yes the hose is a steel line.

 

And....did you hook the torque arm from the rearend back up in front somehow?

 

You cannot just cut and weld a drive-line. They have to be balanced. It has to be done by a machine shop.

 

I don't think JETHRO is listening to anybody, and after reading post 8 an 9 he knows way too much for us to help him. I NEVER KNEW that you could adjust the vac modulator on a Turbo 350 for SLIP

 

Heh, heh, man you're rough!!
After reading post 8 again, I think by "preventing slippage", he was referring to sluggish, higher rpm shifts. You know, like gliding into gear.

 

put the correct trans back in the car with the torque arm back on and use the right driveshaft and all your issues will be solved. biggest rv cam is going to make about 350 lb ft of torque. my driveshaft and rear are handling my engine with no problems, just need a snappier shift kit. it sounds like you have your own junkyard, so try it and see what happens. if you want to keep the wrong transmission in it, buy a crossmember mounted torque arm and have someone who knows what they are doing fab you a driveshaft. i can see you know how to use a tape measure and that is very important. do it right the third time and you wont have any more issues