eh, kinda, gained 20-30 miles on a tank and maybe 1hp at the most.

im also havign the same problem. only getting less than 20mpg. no leaks on the floor anywhr, doesnt burn oil. i have a phat crack in headers, leaky crank gasket and 215k miles, i cahnge oil every 3k, added some oil additive this week. although i do shift at the same speeds, so all pistons are firing.

ummm...thats all i can tell ya.