Originally posted by genyosai
Why do you have to plug this? Does the LS block have the orifice hole on it? If not, does the absence of the orifice hole on the block not suffice in "plugging" the hole in the head?
thanks,
You plug the orifice and then run a line from the back of the block(usually the oil pressure sender) to the head. The head has a pre-existing hole that is plugged from the factory. You remove the plug and screw in an -AN fitting adapter to run the oil line. I suspect the oil orifice in the VTEC heads don't line up perfectly with a flat surface on the non-VTEC blocks, so you wouldn't want something like coolant from the water jacket making its way in there. All you need is a tap and a plug to plug the orifice, so it's not like it's all that difficult, considering the amount of other modifications you have to do.
http://www.c-speedracing.com/howto/lsvtec/lsvtec.php