I think thats the same cam I have. I still lose a little vacuum but I also think that has something to with going to a larger TB. I really wish I was anywhere near sea level, I am sure there is so much more power and MPG's with that nice think air.
I was getting the 302 CEL when Sam (sawcut64) pulled it apart. And yes, it was missing so bad it was hard to drive. I wasn't 100% sure it was the plug and I need an half-baked reason to put BV cylinder heads on the truck.