Clear your cmos (always unplug your powersupply when you do this because power is still running in the board), this should get you running again. And like others in this post have said, you need to up your fsb to 133 and keep your multiplier at 10.5. I had issues with my KT7A right at 140 fsb, technically the 1.4 T-bird came unlocked so running it at 10 * 140 should be possible, but you are taking the PCI/AGP bus out of spec and maybe its just the Abit board, but like I said I was totally unstable at 140fsb.
I do have an interesting question for you, did it crash after you rebooted from making the changes or while you was making the changes? Because it doesn't change anything until it reboots. What might of happened is your having heat issues from your heatsink install and it just took a minute or so to build up the amount of heat for it to go unstable.
One little trick you can do if you don't want to clear your cmos while playing with settings is if it won't boot or won't go into bios without crashing (clearly a sign of instability). Then turn it off, press and hold the INSERT key and press the power button. This forces the board to boot at default settings.
Good luck.