Whats my problem? jetting?

[400exrapes]

I know ive posted alot im just trying to get a feel for what im going to be paying if oil is coming out of my exhaust not being burned but oozing out the tip of the hmf and white smoke? whats the problem if i can fix it i would love to but i havent found the problem and ive looked everywhere all i see is piston but a mechanic told me my piston and compression was good

[underpowered]

could be valve seals leaking oil into the cylinder. but it may also be your piston/rings.

[400exrapes]

what do you think a dealer would charge for that? and if its seals how much do seals cost? and if its a piston should i bolre it or replace it with another stock bore piston