Hey guys thanks for all the info. I went and bought the AC delco plugs. Now I am running MSD wires if everything goes well.

Also I am wanting a cold air intake for my Sierra SLE 1500 4.8L V8. With that I would like to run a Cat Back System also. Any thing I need to know, or will any after market for GM work?

 

Basically any cold air intake will work as far as which kind to buy. You can buy something cheap or buy something expensive, both will perform equally.
Personally, I'm not a fan of cat backs. I'd much rather just replace the muffler for cheap or the entire system.

 

A cat back is a nice bolt on alternative for someone who can't weld and doesn't want to go to a muffler shop to have the work done...but having the muffler cut out and an new one welded in should definitely be cheaper as long as the muffler shop doesn't try to rip you off. The fit and finish of my Gibson cat-back was excellent...just the sound was too tame until I removed the tail pipes and dumped it before the axle. Not sure of the flow characteristics though (not too much info out there about Gibson mufflers, at least not that I've seen)

Magnaflow makes a quality cat-back, as does Borla, and Corsa is tops, but also top dollar.

Many options for a CAI, just depends how much you want to spend. As Joshua mentioned, from my experience they all seem to perform about the same. I'm very happy with my Volant with ram air, but I payed a pretty penny for it. There was a thread in the GM exhaust and performance section about the new VaraRam that showed some impressive numbers...the most I've seen from a CAI...

 

I run delco spark. It is best. E3 not worth. E3 is good for old cars

 

As far as CAI's get the cheapest you can they all do the same thing... It Ýour gunna keep your cats on your truck I would get a 14" magnaflow or a borla xr1 and go to a muffler shop and have them weld it in and dump it over the axle... That's just my opinion

 

ok here is a dumb *** question.... I can not find where to replace my cabin air filter. I took off the bottom of the dash and can not find the screw that is shown in the Haynes Manual. I have already bought the filter. Any info.?

Also, thanks for the info. about the CAI and the muffler. Should I put in my headers first or go just with a new muffler. Does it matter if I keep my cats or not, would it be better performace if I don't keep them. Which is the best rout, cat back system, new muffler with cat back, or just a new muffler?

 

only 99-02 had the filter, what year is your truck? also, once you remove the shroud, in the direct center of the HVAC unit, you'll see a little compartment... the filters are in there.

 

it is a 2003 1500 4.8L V8

 

You dont have a cabin air filter.