Ok, so my guy over at Dart started work on the heads last night (finally!!) and we think we found the problem.
On the cylinders that were making contact, the valve seats weren't cut deep enough. From the lowest to the hightest on the exhaust, we found .050" variance on the exhaust and .025-.030 variance on the intake for valve height from the deck.
We're figuring that the valves have always been making contact since the motor was built two years ago but I may have a spring that's a bit week allowing them to interfere a bit more and bend. We'll check spring rates before reassembly.
So he started with a 5 angle valve grind and set them all the same. Then tapered the tops of the seats a bit more. Continuing on, he did a bit of bowl work to continue unshrouding the valves. He's going to be working on these hopefully this week.
He's guessing maybe around 10 more ponies from the work he's doing but we'll see.
