Best big bore kit

[Fast350ex]

Is the LA sleeve big bore 440 12:1 a good choice for my 400ex?
I believe sthis compression is meant for race gas.

It already has a crap load of Curtis Sparks parts but it's time for a rebuild and I want to do it the best I can.

I'm also looking into a Hotcam stage 2, Kibblewhite valve springs, Wiseco hot rod, Heavy duty head stud kit, and some kind of heavy duty clutch kit.

Would this be a good setup for my MX 400? If so, how would it perform? If not, how is not good?

[eganracing]

That is basically what i have but i have a 11:1 compression. It works great. But when i but a 38 mm carb it was even faster.

[Colby@C&DRacing]

The LA sleeve kit is a good kit. We sell allot of the Ross 440 and JE 440 kits and have had really good luck with them they range in comp from 11:1 TO 12.5:1. I like the ross 440 kit because they make fractional over bore pistons so you can freshen up your 89mm without having to resleeve all the time.

[Fast350ex]

My 400ex also leakes a little bit of oil underneath the exhaust flanges, it doesn't make a puddle on the ground but it sits on the head fins. What is this from? My exhaust is tight on the head, but I don't think it's coming from there. Is it the valve seals or what? If so, how much are they to replace?

I have a Kiehin 39 or 40mm FCR carb,K&N, Curtis Sparks pipe & 416 piston, and other Curtis Sparks stuff.

My engine is getting worn and hasn't been rebuilt in a while, so I'm going for a full rebuild.

Any thoughts or comments are welcome.