I can only back up what David has wisely advised above.
1 If your car is indeed one of the factory lightweights, then it would be doubly important to consider originality issues if you ever consider selling it.
2 Don't underestimate the amount of time , and money this is going to cost. There will be cuts to the crossmembers and repositioning work to be done. Personally I don't think the Mazda box is the way to go , as outlined by David . Yes I know it is a good box with a rifle bolt action, but is just not designed to take the low down torque the V8 produces in abundance.
3 If you want to keep a strong box go for the Rover R380 box (parts for the LT77 are becoming hard to obtain whereas the R380 has fewer issues in this respect), this will take the torque of a 5.7 litre Holden Monaro which pumps out more torque than any Rover engine is capable of. This will also deal with the handbrake issue outlined by David.
4 If you must go outside of the Rover 5 speeds, try to do a tried and tested route and go for the Ford T5 , I think John Eales does a bell housing to mate this box to the Rover V8 engine. This box is also pretty strong and will take a lot of torque without complaining . It is also one in which different ratios are available , enabling you to tailor your exact needs to the gears on offer, the Rover boxes are rather restricted in this respect.
5 Lastly , if you can learn to double declutch, I am sure your current box would outlast the car, as well as giving you sweet changes.
Last edited by MOG 615; 25/11/17 06:07 PM. Reason: poor proofreading!
