my 91 silveerado has that lame ole 700r4, and im wanting to put either th350 th400 in it,which one would be better or easier to swap out..? its has an 5.3 in her now....but im up grading really soon

 

The th400 is stronger, the gear ratios are really close. So it all depends on how much money you wanna spend. If it were me id go th400 and ride.

 

i was thinking the 400, the 6slow might eat the th350, but how hard would it be to change to 400? i cant find no cross members or driveshift nothing...

 

TH400, you will need to modify your current cross member and get you driveshaft made to fit unless you get lucky!

 

could i get and longer yoke for the 400,i know im going to have to get one,right 700/350 uses a diffenert yoke right?

 

700r4/350 turbo are the same yoke. 400/4l80e are the same. Only thing that can be different on them is lenght. long output shaft or short one depending on what trans u get.

 

which th350 did you do when you had ur old school the 6 or 9 inch tail

 

i had a tci short tail shaft 350 turbo. U can order them to be either a long tail shaft or short. I did the short swap for strength. And i thin went to the junk yard and baught a driveshaft out of a early 80s model chevrolet truck. They came with the 350 trans and carbed 350 from the factory. Your stock drive shaft will be to short. One from that model truck worked perfect. I used my stock 700r4 yoke. Worked great!

 

a 350 will be some what cheaper, a built one is pretty stout.. The 400 is def a stronger unit, bu again will def be more money..

 

Mangled how much more would a 400 be than a 350? The only time your gonna be putting some serious money in one will be upgrading all the hard parts