Hi I’m Clive, live in Norfolk , spent far too much time under old vehicles from 70s fords to 60s Bedford coaches, currently restoring a 1982 Mercedes 508D but I want to explore altering another vehicle.

I have done a bit of a search and not found the answers…

I wanted to know what HP the manual gearboxes on the 200tdi / 300tdi can handle, I intend to use a Mazda engine which should have about 140 hp and have been told the manual gearboxes won’t handle it and I should stick to the auto but I don’t want to !
Thanks in advance. Clive..

Welcome.
Sounds like an interesting project.

There are likely to be more knowlegeable people in the relevant forum/section.
There are some that have 'tuned' thier cars up to around the 140bhp (possibly over ?) and use the std 5 speed manual box...

Try asking here .. https://www.landyzone.co.uk/forum/defender-90-110-130.7/

Hi and welcome

Hello and welcome