300ex big bore?

I have a good friend with a 300ex, he wants to make it keep up with my 400. What is the best most reliable kit out???

Paul

[2k2-300exnj]

i have heard the ct racing 330 kit is the most reliable and best kit not sure though fst makes a 390 kit but i dont know how reliable that would be

[400exJOE]

a 330 would probably beat a stock 400. A 390 would blow it away but also cost $3000. a 330 would be my advice.

[300exPA]

I just installed the Powroll 330 piston and sleeve in my 300. The head was ported and the head was decked. The difference in power is unbelievable. I haven't gotten it completely broken in yet, so I don't know how it will perform with a 400. It probably won't the same, but a huge improvement. This was the best investment. I also dropped in teh WB cam and added a stock 400 carb with a K&N jet kit. You would be amazed. The front-end will pull up in 1st-4th.

[300exrider99]

Does the case have to be bored out to accept the 330 sleeve or does it fit right in, and about how much does a complete 330 kit cost including cam and all of the other essentials?

[300EX-Man]

i want to put a 330 on mine too. im probably gonna go with a pro fab kit. they have a sweet kit. everything u need to make it run awsome. carb, valves, springs, cam, hardened rockers arms, heavy duty clutch springs, modded cdi, gaskets, etc.

go to: http://www.profabatv.com/parts_accessories.htm

it has everything, including price

u can even mail in your motor and have them do everything

The cases have to be split and some mill work needs to be done for the sleeve to fit. Depending on who does your engine work you could be looking at around $1,500 to $2,000 for everything(head work, cam, spings, carb, clutch, piston, cdi, and so on). I hear the a 330 kit will beat a stock 400ex and is very reliable. The only time a 300ex engine kit becomes unreliable is when you stroke the engine. Hope this helps, and good luck.

[300exPA]

KBASS24, The case doesn't need to be split for the 330 sleeve to be installed. They bore the old cyclinder out and put the new one in.

[Zero Z400]

In an old issue of dirt wheels they had a 330 and they raced it against the 400ex an it beat the 400ex.