C10 350 to 700R

Hi folks,
need a little help in prep for replacing my 350 to 700R.
Please advise on issues I may face.
cross member, drive,

Thanks
Ray

700r4 is a little bit longer, and the cross member will have to be moved. I don't know about the computer or anything. is it a 700r4 or a 700r4e

Not sure Matt,
The trans was given to me,
and am just looking for better
gas mileage.
Just bought the 85 with 75k org. miles,
its just bad on gas.
The trans came out of 85 impala.

Ray

If the trans came out of a 85 than it is a 700r4, not the electronic one. I don't think you will have any trouble with the speedometer or anything, I believe 85 still used the gear driven speedo. The 4 wire plug on the drivers side front of the trans must be connected though. If not you will burn this trans up. 700r4 started in 1980 I believe. 1980-1985 you must have that plug, (Torque converterlock-up) the newer ones don't need it.