NO production line engine EVER came with W2 heads!!
The pre-production LRT concept truck was presented with W2 heads and manifold (by Tom Hoover himself, no less), but the production version was nixed by the bean counters.
The engine used was designated the EH-1, which was basically an ordinary police E-58 outfitted with the necessary components to enable it to be installed in a truck (different oil pan, pickup, dipstick and tube).
