Can I drive 20 miles with open headers?

[MOBS]

Also, if you get too much drone with the windows up....you'll prolly find it comforting to roll them back down.

 

[chevydan3]

Update. Okay, so we welded new o2 bungs in the new headers, and cut the egr tube off my old shorties and welded it onto the new ones. I threw them on the truck and drove it down to the exhaust shop, it was 2x as loud as I expected, haha. Had the shop run new 2 1/2" pipes from the headers to the cats, and I already had a flowmaster catback with a 3" single tailpipe. With these new headers, I gained 2.5 mpg, from 11.75 up to 14.25. I am very happy. I didn't want chrome headers but the flowtechs and all the knockoffs mostly have 5/16" flanges and these had 3/8" flanges. They are the 88-95 midlengths that are all over ebay. I considered the 96-98 specific flowtechs but feared I'd have driveline clearance issues because I'm lifted. I have pictures and will post them later on tonight.

 

[94Sierra4x4]

I drove about 10 miles with no piping off the stock manifolds. It literally sounded disgusting. I didn't want to take it over like 1500 rpm.. Stock y-pipe back on, and i've got about 8ft of straight 3" piping on there now.. barely sounding acceptable