the easiest mods you can do if you have a stock head pipe you can take off your head pipes and grind down the welds this will help with the flow.
get for $15 you can get advanced timing pin and it will also make an effect. Maybe put a slip on muffler and a high rev cdi box and you should have a nice little set up...

thanks thats some good advice

What's an advanced timing pin?

I would not recommend the step key ignition, I have had 4 of them shear on me. Do not touch your flywheel.

Sparks says not to use the key on 440s or bigger cause they already run hot, and the key makes them run too hot.

Adam Smith

99 400EX

i got a 465kit with a lightned flywheel, 6 degree advanced timing, titanium valves ,Custom race cam, 3-way valve job, port polished, hot rod (rod),customed made cam chain, Lrd big bore exhaust, trued and welded ,had the crank shaved down , alcohol for my 39 fcr carb ,i got an 8 inch swing arm, chromed frame, polished head,case custom design paint on plastic.Never once have i sheared anything.

((((((AS THE T-REX EATS THE RAPTOR))))))

but you wont run hot either because you are running alcohol and your timing needs to be advanced to run it! about the searng i dunno!

Unless you have a built motor the timing advance does you no good, your motor cant handle it. ANd as far as the header mod goes, your increase is not even worth the time you spend filing them down. The CDI and Slip on however will have a little bit of an increase over stock.

Dont forget cam timing you can slot your cam sprocket and degree the cam for some extra ponies.