I have a '87 core that has been rebuilt before and has some odd stuff going on inside. first of all it seems that an 87 should have an aux valve and it doesn't. next some of the are for a later trans but the valve body checks balls are set up for an early. it is a "K" case. the question is should I build this or find a different core? can the aux valve be added or is this a bad Idea? the trans will be going behind a pretty mild big block.