Outer Limits 4x4 Board

I have got a 91 4runner SR5 with the 3L V6 and the engine is getting a bit tired now and im also sick of the c#&p fuel economy so im looking at the options of an engine swap. Id like a diesel but im not sure if there is anything available that would fit in relatively easily. would either the 2.8 or the 3.0L from a hilux go in? or would i be better off to just sell it and upgrade to an 80 series?
any thoughts would be helpful

fitting a deisel into a petrol is a big job,some peolpe have fitted a Commo v6 and are very happy and better fuel aconomy,a Supra conversion would be good to look into