Belkin623

I'm finishing putting everything back together from doing a valve job at home on a 2003 VTR1000F SuperHawk. I go to slide in the valve lifters and they don't fit into their bored anymore! They slid right out with a magnet when I took them out about a month ago, but now they won't even go a centimeter down. I'm very confused as I used engine assembly oil, and the machine shop clean the cylinder heads really well, so if anything, there should be MORE space for it to slide down. All 8 lifters won't fit into any of the 4 bores on each head. Any ideas? I've heard of some people "chilling" them to get them to fit, but I'd like other options.