While I have your attention....

Can I run my stock 4.8 headers with the 243 heads? I imagine it should be fine, the exhaust ports are very similar in size. The only difference I see is the D shape in the 243s.

I realize the stock exhaust will be costing me some power, but cash is tight.

I really want to keep the exhaust as quiet as possible. I've done the long tube with no cats before, and I really dont want to deal with that again. I dont like the raspy wot noise that off road pipes produce, and I hate the exhaust fumes smell. I will definately be running a high flow cat, so I question if longtubes are worth it.

Are there any OEM options that flow better than the truck manifolds?

Will the 2001-2003 ZO6 headers work in a 2003 silverado?

 

your factory exhaust will work fine. Of course there are better options, but it will work fine.

I don't think the corvette manifolds will line up with your factory Y pipe correctly. I'm not sure they are any better either...