Couple Questions..please

[86K10 Guy]

Hi all,
New to forum, have been lurking in the shadows, seems like a very active group and look forward to participating in the forums.

I have a 86' K10 4x4, it has the stock 305 in it and had a couple of questions. First, about my oil pressure guage, it slowly started dropping while driving and is now at 0 psi..does not even move. I have checked the oil and all is good in that department. Do have a rear seal that is leaking but am keeping up with the oil level. I do really need to change that rear seal.

Having a difficult time locating the oil sending unit on the truck. If anyone has a pic of location would be much appreciated and how hard is this going to be to replace if that is what is at fault. How would I test this sending unit?

Lastly, thinking bout an engine swap eventually. My old truck has stock 305 motor with a TH400 tranny and 154,000k miles on it. The little motor still runs good, but would like to swap to at least a 350 motor. How difficult is this swap?

Thanks ahead of time for any pics or info regarding my 2 questions and looking forward to chimming in here and there!

Thanks, Joe..peace <*)))><