Forgive my newbie question but what are the advantages of an e31 head over the e88 if any?

i have an l26 block/e88 head that is stock except for headers. i do plan on doing some mods to the engine but nothing huge.

there is a e31 head that is for sale and i just heard that they are really rare so i was wondering if i should pick this up.

There were several castings of the E-88 head....at least three that I know of.....the earliest ones were almost idential to the e31----but the ports were cleaned up a bit and the coolant pasages changed.....this is the "best" e-88 head...it retains the peanut shaped chamber that the e-31 had, but had the improved coolant passages. It was phased out in the 72 model for one with a slightly larger chamber to reduce C/R for unleaded gas....the 260-z had a e-88 with a larger ex valve and a redesigned chamber to further reduce emmisions. In summary...to answer your question...an E-31 head would yield a higher c/r on a l26 than stock about 9.6:1, but may not be the best way to go.