It took me a while to track down some of the threads for you. These are threads by guys that know how to build what you're asking about. There are plenty of other threads out there too.
13 Turbo
http://rotarycarclub.com/rotary_foru...ht=dyno+sheets
Rice Racing 13B:
http://rotarycarclub.com/rotary_foru...ad.php?t=10423
20B NA
http://rotarycarclub.com/rotary_foru...ad.php?t=15078
20B Turbo
http://rotarycarclub.com/rotary_foru...ad.php?t=15050
Basically 450 HP is not a big problem either way. If you want it naturally aspirated (NA) you have to go 20B and even that's tough to do without spending a LOT of money.
Read over your class rules VERY carefully. Taking advantage of the rules is what will make you competitive in any type of racing. See what best fits your budget and plan accordingly. Some require you to have an engine from the same marquee in the car, some don't. I'm unfamiliar with the particulars of what you want to run in. If you need a light Mazda car the 1979-1980 RX7 and the 1st gen Miata are both very light. approx. 2200 - 2300 lbs. dry street weight. The early cars RX2 & RX3 are also very light but you'll have to work on the suspension, again see your class rules. Once you have the money there are plenty of shops around the country that can set you up with what you need, but you have to be a serious customer as they don't have a lot of time for idle speculation.