I'm looking to build a 350-400 Hp SBC for my 1969 Nova. I'm interested in the Patriot Freedom Series (Promaxx) 64cc aluminum heads for $850. I'm on a budget and was also considering going with a quality Cast Iron head if doing so would save me enough money without sacrificing too much HP. Haven't purchased pistons or a cam yet but the block is ready for build and I have the stock crank. Any advise?