The D5 head was developed by (oops,it was Weslake) for racing. When it first came out it was a dog. They didn't win races. People who could have gotten them for free, used a different head. I remember the talk back in the day..

I read somewhere that they came back much, much later because they could be wildly ported. The ports looked way different from stock D5 ports.

I am guessing here, but I think the D5 head basically doubles the cost of building a Hemi.

As one of the limiting factors of this head is the small, high velocity ports, it'd probably work better in a street application. Again, cost and room are going to dictate triumph or failure. I hope you didn't pay too much for them.

R.