What fuel and (oil does) 2003 sportster a XL1200C take?

I have a '99 XL1200C. With a high flow carb kit and Screaming Eagle exhaust. With the baffles taken out.

I've used the 'Genuine Harley Davidson 20W-50 oil'.

Even with scheduled maintenance, I would pour a quart in every 400 miles. Since switching to 'Valvoline VA1 20W-50 Racing Formula'. Now it's a quart every 1,000 miles.

As to gasoline. I found that Shell Premium runs best in my 1200.
Even with the high flow carb kit. My mpg is 52 on the freeway, at 70 mph. And 35 in the city. With 55 mpg as a best.

Sheilah

You need engine oil, usually 20 W 50, and primary case oil, 50 weight.
Depends on your Climate. Cold, you can use thinner oil.
You can buy from a Harley Dealer, Genuine brand Harley Davidson Oil.