Ok, let me first start off by saying, I'm a huge fan of the inline 6 motors. I've got a bmw 135i with a TT 3.0l I6. Its a great engine etc.

Totally unrelated, I am looking to build a bigger displacement (preferrably american) inline 6 motor with reasonable hp goals.

I am shooting for ~500hp. My idea so far has been the GM Atlas ll8 like the other gentleman here... however seems like to make decent hp.. I am goign to have to rework some internals (which is actually more than fine, just dont know where to begin).

I've got a master fabricator who builds rockets and military aircraft parts etc, so I am 100% confident pretty much anything is possible (and for cheap too!)

Is this motor worth my time and money? The motor itself can be had for real cheap, and I'd already planned on goign with the megasquirt solution as well. My questions were

1) Am I going to need to resleeve, port heads etc, and if so, am I underestimating the work?

2)I've heard people say that recent motors with appropriate electronics should be capable of close to stock compression. Is this true, or can I count on reducing compression to handle extra boost?

I'm very mechanically inclined (tho admittedly never had any custom decisions, like boring cylinders, or sleeving, or custom cam grinds etc), And I've tuned ecus before.

This would REALLY be the direction I'd like to go, but afraid I dont know enough about what I'd need for the boost.