I bought a radiator for my 98 z28 manual tranny.
bottom drivers side corner of the radiator has an extra nipple coming off of it about 3/8's
my old radiator did not have this. I cannot distinguish why some radiators have it and some dont. seems automatic camaros did not get it and all manual radiators do have it according to pictures. but my manual does not.

should I just cap it?

 

Sounds like a lt1 radiator. Yep just cap it off

 

I have 3 extra on mine, They make them generic to fit many cars.

 

freaking lame.
does it being an lt1 mean its the extra capacity?

 

Yes, LT1 rad is bigger than LS1

 

finally something the lt1 has better than the ls1

 

well it was installed with no hickup's so I guess its all fine and dandy.

 

Yea i am using my LT1 radiator on my LS1 swap and I love it. Nothing like having a LS1 in a 95 Z