Don't know where NL is, but as long as it isn't france, then it must be nice
Sounds like you need a good set of heads. That is the secret to horsepower. You need a LOWER compression ratio if you put a blower on it, probably about 8 to 1. I'm no fan of power adders, I think hp should be made the old fashion way. A good set of free flowing heads, no restrictons in the intake or exhaust, and with about a 10.5 to 1 CR (dished pistons) you should have a real nice motor that runs on 93 octane. If you are willing to run it on exotic fuel then up the CR to 12 to 1 (flat top or domed pistons) and 500+ hp is no problem at all.