Hi Kyle,

You can get someone like Wiseco to make custom forgings, but they cost a zillion dollars & give very poor bang for the buck. The difference in HP & Torque output between bog stock bottom end & one that has had stacks of money spent on it is pretty close to nil. The place to spend the most money is in the cylinder head & even then standard B20E valves are all you will ever need on the street especially since standard valves & guides will last about twice as long than their stainless steel & bronze 'race' counterparts.

For headers, you will not likely find any advantage from 4-1 until the cam gets very large and has a lot of overlap. 4-1 are generally easier to tune, but are peakier like you say.

Cheers,
Paul.