I'm torn between these two vehicles...I'd love some feedback!

 Isuzu:

The Isuzu is a 1983 diesel (of course), 4WD, with 160K, for $2700.

Windshield needs replacing, interior is rough, body is decent, faded paint. No engine block heater, don't know much about maintenance, but it drives really well. Not biodiesel ready.

Caddy:

She is an '82 with 200K. for $2300. Interior is awesome, new battery, body is good except for collection of small dents on drivers side, biodiesel ready.

I guess I'm undecided because I know how much the 2.2L on the isuzu vs the 1.6L on the caddy makes a difference (though it's a heavier car), but the caddy's parts will be easier to find. With all these pros and cons, I've confused myself and don't know where to proceed. 

About me: Currently don't own a car, but lately have needed to make the commitment. Only want to run biodiesel, *wants* to put time/money into a truck but in all reality, may not do either for awhile.