Anyone put a Clio 172 engine into a 340 I understand the wiring will be harder and sump will require modifiying anything else? Cheers

Yep. Been done

Got any pics of your 'project'? Otherwise this ought to be in the engine section of the forum

I would expect the 172 engine may be too much for the 340 driveline, you have to be careful when driving any 300 hard, even the 1.4 can break the propshaft if you abuse it.

I've broken two, the first still with the 1.4 and learnt my lesson to be careful with wheelspin after that. With the F7P I've broken one and that was from not feathering the throttle over bumps/a small jump. The problem with trying to toughen up the prop is the problem can just be transferred into breaking the bell housing or gearbox input shaft.