My 1991 f350 7.5L V8 is making a clicking sound?

I Drive a 1991 Ford F 350 7.5 liter v8. There's a clicking sound coming from the engine block it sounds like from the right side of the block on the top from the 2nd to the front spark plug. As I speed up the sound gets faster and as I slow down the sound gets slower. I also noticed my oil pressure get higher as the clicking sound lasts longer. When I first start up the truck and head down the road the sound is not there but after about 5 to 10 minutes of driving the sound will start and slowly starts to get louder and louder. Once I shut off the truck let it sit for a little bit and then restart it the sound goes away but it always comes back after about 5 to 10 minutes of driving.

What is the best website to get custom truck rims from?

I think I want a nitto mud grappler tire. But I don't like the regular rims/wheels that are on them. (Looking at them online) and so I want some maybe all blacked out rims/wheels or maybe red and black rims/wheels and the nitto mud grapplers. So,
Question 1. Where is the best website to buy nice looking blacked out rims/tires online?
And question 2. Also, is it a good idea to, buy these nitto mud grapplers online, take the rims on them off, and install the custom blacked out rims into the nitto mud grapplers? Or is that too hard? And is that more expensive than looking somewhere that has the rims I want already installed onto these tires? I have a ford f250 powerstroke diesel by the way.

Can i just put any custom rims on a ford f250?

Can I put these rims: http://www.wheelsforless.com/HE87879087712N
on a stock 2001-2003 ford f250? I'm wondering because the ford super duty diesels have the lockable hubs up front. So how would that work?

How much is my 1979 Ford F350 Custom worth?

1979 ford f350 custom with a 351 Cleveland. 12,779 original miles and me being the second owner. It's a flat bed with the original rack that matches the paint job. Everything is all original. Used as a hay truck during summers and stored in a barn during the rest of the seasons. No rips or tears in the seat, just a few minor dings here and there but everything works.How much is my 1979 Ford F350 Custom worth