I just bought a 2003 GMC 2500HD. It has 1,100 miles on it now and it's time for some mods. I purchased the predator and it should be here in a couple of days. I would imagine that my truck is past the break in period and I should have no problems with the predator? The truck is the 6.0 with 4.10, and a locking diff. I am thinking about an air box and a cat back for starters. The truck feels somewhat sluggish out of the hole but it is a large truck. I would like to get more punch out of the hole. Anybody know about the factory locker? It feels like a limited slip on the pavment? Any help sure would be appreciated. Thanks Jim

 

Nice truck! After the predator your truck will feel great, I would suggest a UPD intake and a Flowmaster 70 series muffler part # 530513 this is a direct replacement muffler, i'm assuming it is just like the chevrolet HD exhaust. Alot of people have opinions on flowmaster but I like mine, its not too loud. And I like the factory HD tailpipe, I hate oversized chrome tailpipes.
The differential in your truck is a corperate 14 bolt full floating axles with a 10.5" ring gear and eaton G80 LSD.

 

Thanks for the info. I have had quite a few flow masters over the years and love them so I will look into the muffler. How about that UPD intake? Where can I get some info on that? 15.99 is impressive. How did the headers help?

 

UPD recently had a spring group purchase, you can find them at their website www.ultimatePD.com I did alot of research before choosing the UPD. The headers yeah, i'm sure they did something, it is imperative that you have some kind of headers for use with a aftermarket camshaft. So that exhaust has a harder time of getting into other combustion chambers during overlap. If I was to do it all over again I would have gone with long tube headers. www.theotherguysproducts.com or www.flp2win.com have what i'm looking for. I am really enjoying owning my truck, and its always fun to annoy the dodge and F150 boys for their smaller motors drum brakes 6 lug wheels and far less GVW. Hopefully next time i'm at the track I can get mid 15s, have a look at www.tbyrne.com he has alot of performance stuff for your truck.

 

Thanks again for your help. I got in on the Gp for the intake and hopefully will have that soon.