You could look around for a 292 (it is basically a stroked 250 in a taller block) They made them until mid 80's and they had a removable intake still and can be real stump pullers to with a little work. I remember driving some pre smog 292's in late 60's and early 70's and they were very strong running motors then. BTW, the land cruiser has a GM motor because when GM came out with new generation 6's with 194/230/250/and 292 in mid 60's, GM sold the old 235/261 and all its rights to Toyota and though they modified it a lot over the years, a 71 was pretty much a stock "stove bolt" GM 6

Will this work? anybody else heard of it?

Here is a link to some stuff about my brothers and I
http://bus-plunge.blogspot.com/search?q=hemmings