I know this has been covered before and I'm sorry if it was recent. I am new to trucks when it really comes to knowing the ins and outs, especially with a 4WD. I need long tube headers and a catted ypipe for an 02 5.3L 4WD avalanche. Truck is lowered 2in front 3in rear. I see some of you with the early trucks have SW long tubes and cats even though that say it's for 03 and up trucks. Think I can use them with this application? What about the Dynatechs?

If I have everything in my mind correct, lowering the truck will actually raise the front axle and drive shaft. So if the y pipe goes under the drive shaft, then I'll have more room since the truck is lowered.

Any other options? Thanks guys.

 

Im thinking you will probably be fine.

 

Here's a couple shots of my SW exhaust near the front driveshaft. Crossover point is near the crossmember.

 

your drive shaft does not move in an ifs application. I am not aware of any 4ed kit that actually raises the front diff to correct angles, nor do I think you could do it, due to clearance with the oil pan. You should be the same as a stock truck. Any NBS headers and y pipe should work for that application.