Approximate Cost to Buld 375-400hp 360?

It depends on if your doing all the work, or paying someone else to do it. It also depends on the level of machine work that is going to be done, cost of a core, and if your going to reuse parts or start from new. We have a Classic Cruiser 360 that makes around 360-380HP and sell them complete from Carb to Oil pan, dyno run for cam break-in and tuned for $5850. Everything is new or reconditioned to be better than new with new parts(valves, guides, springs, rod bolts, all hardware, ect). e don't reuse oil pans, timing covers, valve covers and things like that, all new.

Yes you can do it yourself for less, but do you have a dyno? Can you port your heads and do all the mods that need to be done to make it a real cruiser that will last forever? Can you set up a valve train correctly(a lot of threads on here about bent pushrods and valves)? Its not that hard to do it, but its not that hard to not do it right either.