if you are going with a hp500 efi cam you need to upgrade the valve springs,bob madera can sell you what you need .eddie young is also very knowledgable and can help you.as stated above,the valve train is not a place to save a buck,it can come back to bite you in the ars.

Using fatigued springs from a low lift cam and re-using them on a higher lift cam will make you wish you spent that $150 on springs...

Scenario: You are cruising along at 4000 RPM. After a short time "Mayhem" stops by. A spring breaks. The retainer gets beat to death and you drop a valve. The pieces get sucked in thru the intake and spit back into 7 other cylinders. With no power you float aimlessly in your lake for 5 days. You starve to death. At your funeral your eulogist says your life could have been saved, this could have been prevented for only $150 dollars.

Spend the $150 and protect yourself from Mayhem. Its just not worth it dude.

10:1 with iron heads......overcamm it. You'll need to bleed of some cyl pressure so it doesn't detonate to death. Stick a small duration ski boat cam in it, and you'll be picking pieces of piston out of the tailpipes.