I hope this will help you,

Here you go I got this off findarticles.com. I copy and paisted it so you can see why you need a turbo plug with a turbo head.

"Turbo" plug. These do the same job as regular plugs-they ignite the fuel/air mixture inside the engine-- but their design offers an advantage. A turbo plug is tapered and doesn't need a washer; It seals the combustion chamber nearly perfectly. Regular, non-tapered plugs with copper washers can allow leakage out of the engine's combustion chamber, and this causes a slight loss of performance.

The taper on a turbo plug and on the mating portion of the head also allows the combustion chamber to be smoother and less likely to disrupt the fuel/air mixture during combustion. ft doesn't matter how long or short the plug is, and there isn't any concern with the thickness or reusability of glow-plug gaskets.

Turbo plugs are sealed against the interior surface of the cylinder head; the tapered part mates with a taper in the cylinder head's glow-plug opening (or "head button" on two-piece heads). This fit means that the glow plug is always installed at the proper height; the interior contour of the combustion chamber is never disrupted by a plug that is too long or too short, and there isn't a gasket to worry about leaking. The result is a potential top-end performance increase of a few thousand rpm.

Are turbo plugs less durable than regular plugs, and are they suitable only for on-road engines? These are popular misconceptions. Having a tapered body does not make a plug less durable. Plug durability is determined more by Its coil construction and how the engine is tuned than by a plug's housing. To seal properly, turbo plugs do, however, require perfectly clean plug and head-button threads.

Off-road engines encounter more dirt and grime than on-road engines, so turbo plugs are more suitable for on-road applications. If, however, you maintain a clean, debris-free head button and glow-plug threads, a turbo plug will work just fine.

Dan.