If money is a concern, and you were going to use "J" heads, why not get another set of iron "J" heads? Good pair "J" heads ready to bolt on will not be anywhere near the price of new eddy's.
If your bottom end is stock a good pair of stock 360 "915" castings would fill the bill for cheap compared to aluminum. Don't mean to damper your party but 350 to 375 reliable horsepower seems like a plan.
