I want 3 simple answers....

[5.0L V8]

That will work Evan, use the STP filter. That makes the deal similar to what those three would cost at Walmart. The parts stores have some of the highest oil prices, so getting the air filter free helps even that out.

The oil filter can go up to about 5000 miles IMO, that's your real limit. How much can the oil filter hold before letting some oil bypass, 3000 miles is easy to say, 5000 is not too much farther. The FL-820S is not a large filter, so don't go over that if you can help it. For severe duty or very dusty conditions like gravel roads, then you'd need to shorten the intervals.

I just threw in about 3 fl ounces of seafoam into my oil. About how long until I do my next oil change? I can care less that I essentially just ruined my full synthetic oil that I just put in 30 miles ago. I just heard its not a good idea to leave that stuff in for too long. I ran a little over a third of the can into the gas, a majority of it up through the brake booster line, and the remaining 3-3.5 oz into the crankcase. THIS 5.0 IS RUNNING *******!!! I HIGHLY reccomend this stuff guys. I've tried Marvels, and it doesn't even stack up to this Seafoam crap. Excellent Product.

 

[CDW6212R]

I've never used it in the oil, just the gas so far. Follow the instructions to be safe. The treatment used through the vacuum lines is the most effective, I hope that helps.

 

[5.0L V8]

Oh man, it helped loads. 5.0 is running smoother than it ever has. Guess i'll do it under 50 miles just to be on the safe side.