484 purple cam..JUNK

"484 purple cam is junk"

That cam has been around a long time and a good piece.

I have always installed them @ 108 on the 340.

Sounds like something else is being overlooked!

Like said before check your initial and total timing. If this is an early hi-po 340 that 650 DP should make it idle and perform pretty good right out of the box. I would be using a 750 DP though.

Some times you do to many things trying to get it right that your tune goes way to the bad and you need to go back to square 1.