i have a 12 1/2hp lawn tractor thats modified. I milled the head 3 millimeters and drilled out the carb jets. I also ported and polished the intake. what else can i do. Any help would be great. it does about 25-30 now but soon to do around 50 cause i have one more pully to change.

Not to put you down, but why would you want to do 50 in a riding mower? You can run a good synthetic to stand the heat, mobil ones good, and run 110 octane.

Has It Have A HEMI??? lol, I don't know much of "soupin" up mowers. But yeah, what bugman said, some synthetic would do ya some good. Make sure you wear a helmet, goin 50 and pickin off a tree wouldn't feel very good the next day. Best Of Luck!

well thanks i just got some good oil yesterday along with a new head gasket that was old and blew when i took of the head to have it milled 3 millimeters

I'm a little bit of a oil person, what brand oil?

Hey Bugman,
Just wanna thank you for all of your help, but i got one more question for ya!! Speaking of oil, what would you use on a rebuilt 10 yr. old engine. Synthetic? Castrol? Quacker State? Just wanna know

Either Pennzoil Platinum, or Mobil 1, I have mobil one in three of mine, they love it, especially the new 18.5 intek. Little lesson on synthetics though, theres groups to oils, group one, group 2 which is conventional oils and are high quality conventional oils we use now, group 3 being hydrocracked conventional oil, after a lawsuit, earned the right to be called a syn like castrols syntec, then group 4 like mobil one which is a pao ( Polyalphaolefins ) and group 5, all synthetics that are oddballs, like redlines ester syn, or pennzoils new platinum eop (ethylene-alphaolefin polymer) synthetic..... actually unlike what some say about synthetics are not true, like its not compatible with conventional, or it causes leaks..... some syns have a good cleaning ability about them, and can clean false seals and show where a bad part in the gasket is. Syns also flow better in cold temps, and stand up to much higher temps.

ahaha, pennzoil also doesn't cause sludge, nor quakerstate ( both owned by shell now, and they make a heck of a good oil called rotella) just another rumor to end there.

how about adding a turbo! i know it sounds different but its been done. the whole crew from xtreme mower mayhem is on this board and have plenty of pics & info to share.

http://s15.invisionfree.com/Lawn_Mower_Central/

i am not sure now but its for charged-turbo small engines and the motor is old so i went for the best to clean the motor out nice. but i will find out what kind.