Having now owned a couple of both, diesel and petrol early G's I have to agree with DAI.
The 280 motor is a great engine, no doubt one of the most free revving, and easy to work on motors that is petrol. It will go a good 180,000 miles before needing top end work if you keep your valves and timing chain serviced well.
But that being said, the diesels are just so much more simple. And running Biodiesel is a great thing to be able to do in my opinion. I've put thousands of miles on G's with biodiesel, getting about 32mpg!
My 280's at best get 15 mpg. MY LWB 280GE got about 10mpg, but it did have large tires.
Also the petrol motors seem to get a bit worse as they get older, and also have fuel injection, warm up regulator, and all that other junk to deal with. They also run weird at different elevations and need to be retuned. Diesels do not.
Diesels don't need batteries, alternators, wires, nothing but some veggies, some oil, some air, and an open road to cruise.....
for those who only use their early G on the street, well, I suppose i can understand wanting to get a bit more accelleration, but the 280 has to be really wound out to be in its powerband (not that its bad for it), you can run those at 5000 rpm all day long if you need to.
The 6.17 gears and the 5 speed, or the 5.33 gears and the 4 speed are the only way to go in my opinion with the 280 motor.
-mike