Harrell,
If you buy a kit you will hopefully get detailed install directions because you only get one chance to do it per kit! The tube is plenty long enough to thread through the water jacket before screwing the soldered fitting into the block on the pushrod side.
Be sure to use thread sealant on all fittings into the block and even on the special compression nut on the oil distributor side. It's a mechanical seal but the goop helps it crimp down on the tube.
Assemble all the fittings into the drivers side block before you bend or kink the tube or they might not slide on.
Threading the tube through the water jacket can fill it with debris...be sure to blow it out before final assembly.
Once the compression nut is cinched down, it's a done deal, it can't be removed from the tube. Good luck and keep us posted.
Stuart