/\ That is one option, but those LT engines have a very spindly camshaft, also it will be at 1/2 engine speed.
However here is a link to another thread, by someone who managed to achieve that albeit unintentionally.
https://listerengine.com/smf/index.php?topic=9009.0To change the DOR of a Lister engine is a lot of work, and you will need to replace the following:
Camshaft, starting dog, starting handle, flywheel fan shroud, and flywheel fan. No need to change the oil pump as these are a plunger design.
Easiest way to achieve this is to find an identical scrapper reverse rotation Lister engine and swap the bits over.
Edit: You will also have to change the flywheel end crankshaft oil seal, because although these engines have a rubber lip oil seal it usually has a preferred direction of rotation, as it has a scroll molded into the sealing surface.