Trying to recon a original box is not for the faint hearted with (as Mike says) parts difficult/impossible to source, and at the end your still left with (IMHO) a pretty poor box.
The S14 swap is probably one of the top "mods" you can do to an S30 and is well discussed/documented from Australia to Asia, it replaces the standard fairly sloppy original unit with a much sturdier unit that feels like a proper sports car shift and will last for some considerable time even with an extra 150 hp through it, I (we) have done nearly 20 of these with good results all around.
The downside is
1. Its not the correct period box so if you’re on the concurs trail then it may not be for you.
2. Its not cheap and will end up between £800 - £1000 if you get someone to do it for you
The upside is
1. Excellent feel to the shift
2. Will handle bags of abuse, even a woman driver couldn’t break it
3. Will last probably longer than the car
The trick is to buy a good unit (occasionally you see ones that have clearly been abused but on the whole the majority are of serviceable quality with the occasional diamond, try to view it first, take someone who knows backlash or binding when they feel it, in the end Caveat Emptor
You can then open the case inspect it and either refit it or recondition it as the parts are readily available
Pay anywhere up to £350 for a unit (S14a is the best of all with the oil trapdoor but don’t worry if you can only source an S14, even an S13 will fit but the internals are not quite as well engineered.
Bell housing conversion £60-£100
New prop £250 (or cut and shut new end on existing prop £100-150)
Modified gearbox mount £50
Quick shifter £60 (gives very nice feel)
Fitted properly its almost undetectable unless you’re the driver.
. Comes supplied with modified prop shaft and gearbox mount bracket as well as bellhousing, so it really is plug and play. There's a few write ups if you wanted to go it alone and source all the parts. Works really well, quite a few people have done the swap. Mine will be available soon.
