additional oil pressure question

I'm installing an oil cooler I bought used.  Since I don't have instructions 
I'm curious about what I might not know.  Have heard that some people (1500 
midget) say the oil pressure relief valve spring deal has to be changed when 
running a cooler.  Also what's the procedure for filling it, just put an extra 
quart in the sump and fire er up?  Any info would be appreciated, as this mod 
was intended to preserve my motor but, if done wrong, could easily cause more 
harm than good.

Thanks!

Mark M.