I own a 1955 series one with a 2.4D toyota engine. I bought the Landy like this, (would never thought of putting anything close to a toy part in a landy) But I am greatly astonished and pleased with it. It runs with a 3 series gearbox, series one front diff and series 2A rear diff. I have never broken a sideshaft and trust me, i have done some crazy places. 

I would recommend this conversion, all i had to fix on the engine in the since i bought it 4years ago was to service the started motor. (which wasn't even a toyota part)The only other main cost of the engine is refueling. I get 8km per litre and a top speed of +- 115. I had a Fairy overdrive as well that made me go about 135+kmh, but seized due to me not noticing the oil coming from it for half an year.. thus it ran dry and now... on the scrapheap. 

I also use cooper sst tires 16/265/75... and I with the correct tire pressure I can go on sand where all other petrol models go and where 2.4Hiluxes dream to go. On rocks the low torque of the diesel engine is superb. The reason for my big tires was to take some revs down and decrease power... it worked, but i still have enough power and torque for any hill. The 2.4 on a short wheelbase is definitely an option to consider. Thank you for running this webpage... its awesome!