Keep the LQ4, put a LS1 or LS6 intake on it, put a F-body oil pan on it, and a big cam like the T-rex or Magic stick and you will be right at the 400 HP mark with a good tune.

Or you could put a small blower cam in it and a turbo and make awesome power and still get way better gas mileage than you would with the 383.

That it just my opinion so take it for what it is worth, I just feel that the LS series motors are a way better platform than the old school small block chevy's.