We did one in a S14 pumpkin w. 4.08 gearing and installed in 1998 s14. We also did one into a Z33 pumpkin with a 3.9 gearing as I recall.
The biggest hassle is getting matching output shafts with the correct spline count to make it work. I know I have sourced 2x2x2 and 1x1x1x1x1 units that fit the helical.