EEEEwWWW - I'm gonna have to step in this big time.
First, I'm quite a rotary fan. I understand their issues, in fact, I've always referred to them as the pistonless torqueless wonders. They generate a stunning amount of exhaust heat. We're talking GLOWING exhaust is normal. In fact, if you have headers and they aren't glowing, you're throwing in too much fuel or driving like a pussy. Next, the issue of fuel consumption. A rotary engine sucks as much air as a small block chevy (well, close when stock - more when modified), so they are going to consume fuel in nearly the same fashion. The good news, is they like cheap fuel. Exhaust noise. There is no engine on the freakin' planet that is louder than a rotary (in a car) and the pitch is equivalent to fingernails on a chalk board if you are foolish enough to run an open exhaust. Mufflers are your friend. Big stout ones. Seriously.
A 13b comes in two basic versions, four port and six port. The four port really digs on a street port, the six port is already better so you only gain a little bit. With a street port, headers, and a decent intake, probably 175 to 180 horsepower. Decent, but not mind blowing power in a 914.
The problem with this conversion, is the Weber and the choice of a street port. The idea behind a street port is that you have a streetable engine. The big weber is a cold blooded bastard for daily driving. I know this probably will make you gag, but a small four barrel holley or edelbrock with an electric choke is a MUCH better choice in my humble opinion for street driven vehicle.
Now let's talk race. Let's talk about a nice run on the darkside... What can a rotary do for you? Well, if you really want to dig into the engine, look up on the forums. We're talking crazy horsepower. Lotsa dyno bragging goes on, but without question, I've seen normally aspirated 13b's in excess of 300 horsepower.
I had a Fiat x1/9 with a normally aspirated 13b. It was a blast. Not in the same league as our spyder, but quite spritely, certainly better than the 67 horse the car started with.
For this 914? It's already plumbed for a radiator, etc. How do you feel about turbo subaru engines? If you want to make a 914 go fast for cheap, a turbo subaru is "all that" and then some.
angela