swap auto for manual

[V12Smig]

Part of the refurbishment of my SIII XJ12 I would like to fit a manual box. I have been offered conversions from different sources; the 5 speed Cosworth/transit box, the XJS 3.6 box, a 5 speed Supra box or I could fit a 4 speed from the E type V12. Does anyone have any thought's or views on the above... I obviously would like to take the safest but also the cheapest route which seems the E type box, I'd actually be happy with 4 manual ratios and would not have to change the diff as you would need to with some of the conversions..

[mike020150]

By the time you've collected all the necessary parts, I'm not sure any of the alternative boxes would satisfy your criterion of 'cheap'! The V12 produces a lot of torque so whichever box you choose needs to come from a high torque application rather than a vehicle simply producing similar power otherwise you could wear out bearings and shafts quicker than planned. Going to all the trouble of making the conversion, it would be a shame not to aim for five speeds despite the relative ease of fitting a V12 E-Type four speed box. Why not consider a Jaguar four speed plus overdrive unit with a V12 bell housing? Plenty of people have made these work behind a V12. Mike.

[V12Smig]

Thanks once again Mike for your feedback, when I say cheap I mean as reasonable as possible, I really don't want to spend loads 6K + on a conversion, but if I can get it done for half of that or near enough I'd be happy and able to part with that amount... I've been quoted 6k for a used Gatrag conversion, about the same for a new T5 conversion, OR have seen a supra conversion for half that amount which retains the standard diff..... all are able to accommodate the modest (by todays standards) torque figures. I suppose I was hoping for someone on here to say, hey, I have a reasonably priced kit for you. I really like the idea of a manual V12, still have strong memories of smoking a E type manual V12 some years back...

[cafcpete]

Have you spoken to simply performance?
They have done a lot of conversion work.
https://simplyperformance.com/v12-5-speed-conversion/
https://simplyperformance.com/wp-conten ... t-2018.pdf

[East Cardinal]

Have you made a decision on which gearbox you will use for the conversions?
I am just looking at the same conversion and simply performance kit looks
good.
Will be contacting them for more information.
Would be interested to know if you decide on a different set up.

[V12Smig]

I have not yet made any decision here, cash flow in these current times has been an issue.... but yes the more I delve in to this the Simply kit looks the most promising one, but it does mean a change of diff as well and that just adds to the expense... will keep you guys posted