definitely would suggest upgrading injectors and fuel pump. the ones that came with mine suck. also will probably need ls9 map sensor to help with tuning. can't think of anything else at the moment.

 

I've got a flex fuel LMG. I think my injectors stay put.

 

not positive if the same. I have some 52lb ones off of a flex fuel 6.2. also put flex fuel pump recently.

 

What's the best header and catted y pipe setup you guys have found so far? I want it as quiet as possible but still flow like it needs to.

 

Going with kooks 1 3/4" headers with catted y-pipe, I think, unless I should step up to 1 7/8"? I was thinking 1 3/4" to keep boost up or should I just step up in pulley size. I have been told stay with the smaller choice when boosting??

I'm also on the fence with catch cans, I'm trying to decide on elite or RX. Any input?

 

I think most will argue for 1 7/8" on boosted anything. That's what I'm finally thinking about at the end of season.

 

if you're actually doing the 6.2 swap later, you'll be glad you went bigger.
if you stick with the 5.3, 1 3/4" will work fine & have a slightly better low-end response at the expense of a little high-rpm flow (which, in a stock longblock truck won't normally see a lot of use).

 

If you're putting a blower on it, you can't put too big a header/exhaust system. It won't hurt low end power because the "exhaust pulse tuning" theory does not apply once the intake manifold is pressurized.

Sort of like how good exhaust systems for turbo charged rides is also different.

For N/A applications there can be great benefits to having the correct system, and yes sometime smaller can be better.

Don't ask me to spec a turbo exhaust....lol

Exhaust for supercharged applications can't be big enough and this priciple can also be applied to Nitrous set ups.

Do it once, do it big.

 

Eh, the effect is still there.. We even use scavenging on turbo applications...

 

Scavenging on turbo? I totally don't understand.