I was trying to order valve cover gaskets for a 87 2.9l v-6 part no.50312 followed by either a letter c or r or t my question is what does the letter mean or repersent?

 

Welcome to the forum


Not sure about part number since all makers of gaskets use there own numbers

But C or R for valve cover gaskets would usually mean Cork or Rubber
Cork seals better long term since it will swell up as oil on the inside comes in contact with it, but it gets hard over time so isn't reusable after a year or two, have to replace it if you need to work on engine and remove valve covers.

Rubber doesn't seal as well but is reusable so if you work on the engine alot then rubber is better to use.

Trick for good valve cover gasket seals is to make sure the thin sheet metal valve covers are flat and true.
The metal bends easily so after it is tightened down once it deforms at the bolt holes, especially if someone over tighten them, lol, so after removal you must straighten it again, use blocks of wood and hammer to make it straight again

After market aluminum valve covers are thicker so don't deform

If you use rubber with original thin metal valve covers then I would look at also adding a few Load spreaders, may need slightly longer bolts.

Google: valve cover load spreaders


Also a "Heads UP"
In 1989 the 2.9l got newer head design and used different valve cover gaskets
Yes you have an '87 BUT............if heads were ever replaced they would have got the newer design

Look here, about 1/4 of the way down, for pictures of the 2 different heads used: http://www.therangerstation.com/tech...2_9_Page.shtml