i am having problems puting a new piston and rings in my 426. i don't seem to be able to install it from the bottom. the oil rings seem to not want to squeeze down enough to insert from bottom. i used a ring squeezer, and sliped it in from the top with no problem, but there isn't enough piston sticking out of the bottom to get the pin in, without letting the oil ring decompress. there must be something i don't know!! any advice from someone who knows????