Toyota's had to do something as it's 4.5l diesel V8 was pretty gutless and used way too much fuel for the power it generated. The reason many of the 79's with the V8 have a loud exhaust is an after market exhaust has been fitted to try to squeeze some fuel economy out of it.
My 5.7l V8 Hemi 4x4 not known for being economical actually rivals the Toyota V8 diesel in the fuel economy stakes while killing it with power and torque.
