what is the best kit

[quadracer007]

I'm looking to put a big bore kit in my 99 300EX wich is the better and most relible kit to use. I have looked at a weisco 330 kit, powerrolls 314, 352 and I have found one I I'm not sure who makes it its a 390 kit any info would awsome

[rooster300ex]

Whatever u do make sure it is done right. The 390 is a curtis sparks engine,great engine builder.

[bwamos]

The 390 is a 330 stroked, I beleive (probably wrong though, lol).

I've been running a 330 for 5 years now. Very reliable and a lot of power. With all the correct mods (port/polish/valves/cam, etc..) you can nearly double the HP & Torque of a stock 300ex.

[99_300ex]

well i think i heard with a 390 you prolly wanna run with an oil cooler am i right? and that is prolly for the pretty serious 300ex racer. i would go wit the 330 if i were you i have heard they can beat some 400ex.

[Konaracing]

I recently finished upgrading the suspension and I'm looking at the engine next. Does Four Stroke Tech have a kit as well? I was hoping to go with a 330 kit, concerned that a larger kit might have reliability problems. I don't race but want a little more power for the trails. I don't want to go to a 400 because I like the feel of the 300 chassis and seat postion. What kind of price range is out there for the kits? Thanks for the info.

[prepracing]

http://www.fourstroketech.net/main.htm has all the prices on their website