QUOTE(lapuwali @ Apr 27 2004, 05:47 AM)
TWM makes Weber clone throttle bodies for several carb styles, including the IDF.
The only issue with these, or any other individual runner induction system, is measuring manifold vacuum for speed density systems (like the Megasquirt). Just one port has too much pulsing to be read reliably. A MAP plenum can be used, or you can use only the throttle position as the load input, which comes with its own set of problems. As a rule, you can get such a system working great for racecar needs, but getting good low-speed drivability is a real challenge for a street setup. The most effective setups use both throttle position and MAP for load, based on RPM (Megasquirt only uses throttle for acceleration enrichment out of the box).
You just tap all of your manifold runners for a small vac. line and run them to a single point. Then run a hose to your MAP sensor.
If you have problems (big cam) with your MAP, stick a mig welder (.023) tip in your hose, just before the MAP.
TWM, Jenvey and CB perforamce make TB's. CB's is the cheapest, but both the TWM and Jenvey are of better quality.
They have the same problems as dual carbs as far as the linkage goes, where as a single TB system doesn't.
Also I prefer direct injection over the injector in the TB, as all these TB's have.