The 203 cam is the largest you can run on unmodified stock 8.1 heads. At .540" lift, the valvespring retainer will hit your intake valve guide with stock heads. Bad things will happen. You cannot use stock pistons with the 205 cam either.

Thanks for that, I was aware of this but interested if anybody has experience of the uprated valve train in standard cast heads going good or bad with the BP205 with the correct forged pistons.

The stock 8.1 heads will really limit performance potential of the 205 cam. The stockers suck. Look into Raylar's 315 cnc heads or Dart's Iron Eagle.

Here's a link to a Raylar build I just finished.

Test ran the new Raylar goodies