engine mods

[400EXKS]

sup guys new to the site here hada few ?'s on wat yall think i shud do to my 400ex...rite now i just got an fmf pipe-n jetts that came on the bike..i wanna start puttin money into the motor cuz all my buddies r gettin 450r's and yfz 450's and blowin me away but i like my 400 and wud rather keep it and make it faster vs. buyin sumthin diff....wats everybody think i should start doing first?..kind of a limited budget but need do as much as i can before i hit the dunes in march

[81 clark racing]

416, 426 or 440 build your call. port and polished head and hot cam stage 2 and you should be good 2 go