I own an 86 IROC and my 700-R4 is gone. I am wondering if it is possible to swap a TH-400 in its place. Would I need to change anything like the driveshaft, torque converter, etc??

The reason is because I currently have a th-400 and don't have the money to spend on a rebuilt 700-r4. Would it be more expensive doing modifications to the current car to do the swap?

Thanks for your help.



Chris
86 IROC
350 (to much to list)...

 

i did that a while back......you'll need the Hurts Swap kit so your tranny mount will line up and it has provision for the torque arm. you'll need a new convertor and a new drive shaft.

 

The driveshaft will be a lot shorter. You'll also need a TH400 slip yoke for the driveshaft since the TH400's is larger than all the other GM trannys.

Swapping in a TH350 is a lot easier.

The torque converter is a judgement call but it's best to buy a new one with a better stall speed anyway. The same torque converter will fit on TH350/TH400 and late 700R4's however the TH400 converter uses a different bolt pattern on the flexplate. An aftermarket flexplate will have the dual bolt pattern for both types.

 

I think they caught everything you need to know!
BTW stephen 87 IROC - I'm just finishing up my 505 cu 85' IROC with Dart Pro-1 ported alum. heads, 1050 dom., hyd. roller, Eagle 4340 4.25" stroke crank, 4340 H-beam 6.385", JE 11:1, TH-400 full man. reverse, 9" art carr conv., ford 9", locker, 3.70 gears, strange 31 splines, but mine is a street car with 4 wheel x-drilled disc's, 17" torque trusts, 315/35r17 BFG drags, 5" harwood and a 6-point cage. I'm glad to see another 3rd gen with a BBC, when you stroke it your gonna love it!!! RPM from hell !!!!

 

I don't need to stroke it. Going to alcohol I should be running mid 10's next year. Going bigger than 468 will mean to many changes. My heads won't flow enough and the headers are too small for a bigger engine or I'd go right to a 540.