The Eddy heads won't give you much more compression than you already have. I have the same engine in my 77 pickup, with closed chamber heads and now instead of having 7 to 1 compression, I now have 7.8 to 1 compression. Not a very big gain. The one advantage to having the Eddy heads and RPM intake, is that you will get much better air flow into the engine. The cams you have listed will kill low end power and in your rig you need all the low to mid range power you can get. I run a Summit Racing #6400 cam and I'm very happy with it. It has 214 224 duration @ .050 lift and .444 .466 valve lift. It is very similar to the factory HP cam from the 60's and early 70's I tried a Hughes Whiplash cam, installed it per their instructions and never could get the motor to run right.. Some guys have good luck with them, but this was my experience.