Converting to the 5-speed and using a non-stock Renault engine meant that could expect to have to make some modifications:
To manitain the correct position of the engine/transaxle, I elected to bolt the 'new' gearbox to an original type case. This would allow the use of the stock engine mounts to partially locate the assembly I could then verify interference, centre the unit and adjust its height so that the half shafts were the correct distance from the chassis. I measured another S2 and found that the top of the output shaft sits down 208mm from the top of the rear chassis rail.
The 821 case/395-00 box mounted in the chassis.
Yup, the 5-speed is too long. The shift arm is resting on the hoop underneath, and the box needs to sit a few inches lower. As expected, a new crossmember and mounting setup must be made.
GM V8 auto transmission mounts. Very bulky but cheap, solid, easy to use.
So, after installing the engine it became clear that the rear hoop would have to go early in order to allow the gearbox to drop far enough to measure and design the new mount. I figured that the bolt in rear suspension crossmember would suffice to hold things in place after I removed the existing crossmember, so I went to bolt it in and ...
SURPRISE! At 34.25" wide where the crossmember bolts on, the aftermarket frame is .25" narrower than the original. And the frame Ian bought from Marcel, and the one in Marcel's shop and Marcel's jig...
Nonetheless, Marcel assured me that because he had a good jig, that the frame was straight and would be fine to use. So, it is inaccurate but accurate. Uh huh....
Out comes the engine and a quick setup with squares and a laser level proves Marcel correct, the frame is straight, at least within the tolerances of my ability to measure.
In the interim, Marcel had offered to repair the frame for free, though shipping would be my problem. I would have to crate it (Marcel charges $200) and ship it both ways between Toronto and Montreal (several hundred each way at least) or drive the 11 hour return trip twice. Having him make it right would cost me nearly half of the value of the frame!