@ ma23 - Good try, but that is a DOHC motor. I can make tons of power out of a DOHC, but I prefer OHV. You could probably get even more power out of yours (and maybe efficiency too) by using 32V and VVL.
@ Deskjetser - Those are pretty good. Roughly same power with more efficiency. The redesign is also the same price. The rebuild of mine costs substantially more and has significantly lower reliability, however. Overall, very nice job. I am open to a rebuild. As you can see, mine is a replica of a GM LS4 5.3L. If you follow me on the forum much, you'll know almost all of my engines are Small Block Chevy builds. My car company is a tuning shop building cars American Motors style, which means using parts from other manufacturers and Frankenstein-ing them together. I see no reason why I can't Frankenstein someone other than Chevrolet into my cars, if they are good enough.
You know my criteria. Let me know what you can put together for me. PM me if you need more info or have questions. You can try to throw a turbo at me, but it needs to be designed for a 1600kg car, which means I4s probably won't cut it. I love I6s except they are terribly difficult to fit into many cars. V8s are far more reasonable for fitment, but huge gas guzzlers.
If you need a test car, let me know. I have 2 I am currently working on. I have to rebuild a ZX model still, after the Steam update, so that one is not currently available. I would actually like something a bit larger for the new one listed on my company page. It is currently running an LS3 in the 530hp range at 21MPG.