400ex rebuild ?s

[rdw03400ex]

ok i need some info. im about to tear my quad down and get it rebuilt but before i do i need some info or advice. first off let me start with the guy whos doing the rebuild for me. he knows his ***DELETED***:grr: for sure, he builds tons of quads and dirt bikes every yr, but i want to get a few more opinions before i spend money that wasnt needed to be spent. heres what he wants me to use, a je10:8:1 426 piston, curtis sparks cam, and he wants to port and polish my head. the ?s i have are if i use the 426 piston with my stock sleve its going to be thin obviously, but will it be reliable or should i go with the 416 piston. second how much of a difference does the port and polish make? is it worth $350? im not going to be racing the quad just trail riding but i would like to keep up with the 450s i ride with. right not im running a 14 tooth front sprocket and i have a full lrd exhaust. any info would be greatly appriciated asap cuz i wanna start buying my parts very soon.

thanks!!

[400exMO]

Make sure the sparks cam is not hardwelded. Or else yout going to need hardwelded rockers, etc. between the 416 and 426 there isn't a huge difference, if you're worried go with the 416. Port and polish is a nice addition to your build if you have the cash do it. You might also want to look into carbs. A 450r carb will make a nice addition to you build as well.

[drew416ex]

I would say 416 with 11:1 compression. The sparks cam requires hardened rockers so maybe a hotcam stage 2. I used this setup for a while and never had a problem. I could also hang with 450's pretty decent. The port and polish is a deffinate benefit on the 400. its worth $350 if done correctly.

[rdw03400ex]

cool thanks, ill keep everyone informed.