Is it hard to swap the 3k to a 4k motor and what parts would i need to do so?

a 4k.

4k would have the internal regulator alternator on it, Where-as 3k (ke20) has external, so you'd need to swap the mounts and alternator off it for it to work, or change the wiring to run the other alternator.

 

You'd need the ke20 mounts on it, and ke20 waterpump and fan, the rest should be pretty much slap together and drop in

Thanks for that, I've seen a motor for sale but doesnt say if it comes with a wiring loom will i need it or will the ke20 one be fine? Cheers

There's not much wiring on a K so pretty much forget that.

 

Just get the 4k, strip it down to a "long block" and just transfer all the 3k bits on. Carby, dizzy, alternator etc etc.

Cheers