Alright, I have a ;92 ls block that I am replacing w/ a '91 block. While switching parts over, I noticed two things that were different on the back of the 91 block. Below is the picture of the 91 block w/ the two things indicated in red.

I've looked at the manual and do not see what they are called. Question is, do I need to hook anything to these or will I be fine leaving them alone. Don't think it makes a difference, but the '91 block was used in an ls-vtec.

 

I dont know jack **** about any B-series but i know that the one on the right looks like a knock sensor with the connector part ripped off , and the left looks like an oil pressure switch maybe.

 

the one on the left is your coolant fan temperature switch. It turns on the cooling fan when your engine coolant gets to about 185 degrees. The one on the right, i'm not sure of.

 

If thats his coolant fan temp switch, then whats that green connecter next to the one circled in red?

 

After looking some more, the one on the left coolant temp switch and the right is the knock sensor for lsvtec. Thanks for the replies....