[Coley]

A very cool conversion for the truck that might make some sense is to put in a 6 cylinder diesel in order to get better mileage, noting the costs of fuel/petrol in the U.K.
The 6 cylinder engines typically found in the Toyota Landcruisers was designed largely around some of the great attributes of the straight 6 GM engine of the 60's....so it is a very easy installation and conversion.
These GM 6 cylinder engines came in a few different sizes...including 230/250 and the big 292 cubic inch sizes (approx 4-5 litre engines)..which is similar in size to the Toyota 6 cylinder diesels.
On the other hand...if mileage is no issue and power is the preferred route...then stick with the small block chevy.
All Good
Coley