the 200 4r would be alot better to use IMO.I did a 200 4r rebuild in my 85 monte ss and used a 3,600 stall converter with a Constant Pressure Valve Body http://www.performancetransparts.com/2004rconstantpressurevalvebodystreetstrip.aspx
With this the cable will be for shift points,The 200-4R is very close to the legnth of a TH-350,No need to cut the drive shaft,