Originally Posted by kenmar
What you do is buy a M5x with good compression, do a refresh on all the gaskets (incl. the head gasket) and then swap it in. With all the gaskets/seals done, the bottom end should last longer than your shell would hold up
Yeah, but if that was the case you might as well spend the extra $300 and put in a MLS gasket like cometic, and a set of ARP's and you're good all the way to 15psi and 350+whp.
In reality it's not expensive to put together an engine. A set of forged rods like Manley, or Crower can be had for less than $500, and pistons come it at around $750. An if you're using an iron block, you're laughing till you hit 500whp. It's the proper assembly and machine work that tells if it will last or not. Like Devon said, it's the assembly that separates the men from the boys. We're working in 0.0001 of an inch in some cases.