You remove the valve cover to lock the cams in place at TDC. I reckon you can do it without removing the valve cover but you'd have to be real real careful, and you'd have no way of knowing if your timing was set truly correctly.
98.5 SVT
91 Escort GT (almost sold)
96 ATX Zetec (i brake to watch you swerve)
FS: SVT rear sway bar
WTB: Very cheap beater
CEG Dragon Run - October 13-15