rover ex buick v8 was certainly a popular swap in the hilux,
i'm presuming a similiar size engine bay.
always thought it was supposed to be light weight being
an aluminium block...
outputs were low by todays standards, think my classic
range rover of '74 vintage kicked out 130bhp, but thats
4x4 detuning back then. think when the 3.5 gained
thottlebody injection output waent to 165bhp, the 3.9i
was much better for torque and offered about 190 bhp.
that said i recall a fast car mag from late 80s building a
rover sd1 as a (sierra) cosworth beater project was
saying 200+bhp from carbs to match the jelly moulds
then 204bhp in first whale tail incarnation. guessing this
would be with a fast road cam etc.