Rocker shaft stands will be the same height for both Eddy and cast iron heads. Yes, you can use the stock non-adjustable rockers and push rods with your cam, but the rocker arm geometry will be slightly screwed up. Shiming the shafts might fix it. As long as you have some lifter perload without bottoming the lifters out ( highly unlikely you will do that ) things will work. Also highly unlikely you have burned / bent valves when you ran 106 - and the compression is the same ( although low )accross the board. Used cam::: Did you verify it is what the seller said it is? Did you check part numbers / mike the lobes, or at least eye-ball them and the lifters when you changed manifolds?