Were you using 4X4 trans. cases? They are thicker and stronger than 2WD models. GM 4X4s also use a cast aluminum inspection cover, and the inspection cover has bosses for tie rods that go from there up to the motor mounts. This stuff is there to resist the extra torque that is applied to the trans case from the transfer case. On older GM 4X4s, there is a cushioned mount that attaches the side of the transfer case to the frame, instead of the braces to the inspection cover. You need something like this to avoid trans case breakage. Your new bell housing (scatter shield?) will most likely serve the same purpose.

'70 CST Blazer, 350, SM465, NP205.
'87 Suburban 4X4, 350, 700R4
'88 Chevy PU, 4X4, 350, 700R4

 

I didn't know the there was a different case available. I was thinking of getting a 700R someday, are their 4X cases stronger too?

Chevota

 

The TH350 and the TH400 "4X4" definitely have stronger thicker cases and the tie rods that Blazer70 described (which incidentally are torqued/twisted/tweeked? in the opposite direction to resist the torque between the engine and the transfer case) but I don't know about the 700R I would think so though???.
By the way replacing your inexpensive easy to rebuild T350 for a 700R would in my opinion be a mistake,
The ONLY gain would be the OD and most people don't use it anyway!
The fuel savings would NEVER pay for the swap-over expense.
If you just want a stronger overall tranny a T400 would be perfect! (you ain't gonna hurt that!/wwwthreads_images/icons/wink.gif)

 

Scoobydoo:

I do want the OD. I like to cruise around 80-100 on long drives, 4000-5000 rpm with the TH350. Plus I would like the lower first and second gear. The only reason I haven't done it yet is I don't trust the 700's strength.


Chevota

 

If you do want OD and want all the strength, get a 4L80 which is basically a TH400 with OD. They are a little costly but you can get them from online salvage yards and I recently heard you can steer away from the transmission computer with a manual system this company sells.

Shawn
87 K5
few mods

 

Well, I checked a coupla years ago on the 4L80, it was $2500! I'd rather have a Gear-Vendors OD because I'd just break the 4L80 eventually.

I did check on the heavier 4X case, The place I called sells used/new hard parts to trans shops local. They laughed and said if I called around I might find one in town somewhere.
Translation: $$$$




Chevota

 

Ok here's the deal with the Ultra-Bell bellhousing. I cut up my trans to fit it on, looks trick. I slap in my converter and try to bolt it to the motor. It won't fit! the bellhousung is so thick there is no room for the converter! Sigh..... It was a smaller 11" converter too. So I had to have the truck cuz I'm in the middle of a move, so I put in a 10" converter. Real fun pullin' a loaded trailer with 3000 stall. Sigh.........


Chevota

 

I recently checked www.car-part.com and found a couple 4L80's going for around $1000. Sill lots of money for a used tranny.

Shawn
87 K5
few mods