400ex piston

[Penler]

sry bout the noob questions guys, but when it says on .40 over, wat does it mean, is this high performance and do i need to change sleeve or just install the piston....

[440exking]

Get the sleeve bore over to .40 over then put it back together.

[Penler]

how much would this cost, and how much more horsepower would i get? is it worth it? what about reliability

[underpowered]

.40 over is = to 1mm, so the piston you have would make your quad a 406. you sill see som eperformance gain, ecspecially if you have a higher compression piston like 11:1. as far as reliability, it wont really change with such a small increase in displacement.

[Penler]

ok so i want to get a .40 over 11:1 high comp piston? who should i get it from wiseco or je

[underpowered]

i have always liked JE, but i am running wiseco now with no problems. it is up to you but i say most people will tell you to run JE

[Penler]

alright and with this i can run normal pump gas? do i need premium? and how much horsepower will i gain is it worth the money...

[underpowered]

you would need to run premium.
Horspower really varies depending on other mods, who built the motor, ho many hours on the motor, tolerances, ect.... to put it simply, it will be worth it and you will get a noticable gain.