4k Head Work

hi guys. my freind and i started pulling his 4k apart last night. we giving it a little freshen up as its going to get some abuse via a sc14 blow through set up. the motor is in very good nic and doesnt require re boring just a light hone. now with the money saved from not having to head to the engine re conditioners we were planning to get some head work done. what is the best avenue of attack? we were planning on getting it ported by the local head joint (they have a good reputation) and may be a three angle valve job with bigger valves and stiffer springs. were can we get heavy duty springs and bigger valves or do we have to use parts out of a different motor. i know there is a few rally guys on here so feel free to crawl out from under your cars and point me in the right direction.