[GT Drew]

The danger of the DOD system is that they are the old weak lifters. And the trays wear the regular lifters can turn and tear off the roller and wipe out the cam. Then there is the DOD lifters. If your oil pressure is too low when it tries to engage. The pin doesn’t properly release and you have the lifter collapse. The two sources that cause that is either the original LVOM leaking, #2 cam bearing worn and bleeding off pressure, or the oil pick up O ring is leaking air into the system which lowers the oil pressure. DOD delete is the cheap way to fix most of the problems. I’m going to fix the problems AND keep DOD.
GenV engines like the LT4 have DOD. The new DOD lifters can handle .551” cams and the updates LVOM are sealed and riveted together so they don’t leak. Lastly the pump O ring. They wear out faster because of the single bolt retainer. It does allow some movement through vibration over time. When the O ring gets older, that vibration cracks and causes the ring to leak. A two bolt retainer fixes the movement.

 

[Jesse Eakin]

Not sure where you want the HP to come from? You keep saying things like, oh other people have made this much power but I want my setup to do it. Sounds like you still have stock mid pipes on the exhaust. DO A FULL EXHAUST and get a proper tune. I’m willing to bet everyone with the power you want did more. You’re going to have to do more too. And trust me. Do the DOD delete. You’ll be wondering why the hell you waited so long to do it after it’s done. Also. Like others have said. The FAST manifold and larger throttle body really aren’t needed for what type of mods you’re talking about. When doing the work on my car. I asked the shop about those same things and THEY told me to keep the stock ones for now. For the record, my G8 makes 386 to the wheels with a very mild cam.

 

[GT Drew]

I agree on the full exhaust. I learned that one too. I deleted mid muffler and resonators, replaced the rear flex couplers and added 2.5” Stainless Works Turbo mufflers as axle backs. It worked. But Solo used my car to test fit the 3” system. I got the Mach balanced system installed and felt the difference the first time I drove it. If you only want a couple mods and don’t care about the HP numbers. Mod the stock piping.
2.25” piping is too small for stock cam. Add headers and a cam, you will never make the HP you should

 

[R1toG8]

I added a set of cheap $400 Pypes 4 into 2 into 1 headers and a Vararam intake, to the cat back system with Magnaflow mufflers that came on the car when bought. Dyno numbers below, made just about what you have but mine

was still on the stock

tune only. 358hp/378tq after tune.

 

[Featherburner]

I put down 369/394 with ARH long tubes, hiflo cats, xpipe mid-section, and Dynomax Ultraflo's. Vararam, UDP, Circle-D converter, and a tune. Since then I added 3" pipes all the way to the bumper, a rodmodded/ported intake and TB. I'd say that added 12-15 more HP.

 

[95wagon]

ARH long tubes

1 7/8 I am assuming?

 

[PONY MAN]

1 7/8 I am assuming?

Correct. Should be 1 7/8" x 3"

 

[Featherburner]

1 7/8 I am assuming?

Correct. Should be 1 7/8" x 3"

Yes, they are 1 7/8" x 3" into 3" all the way out.

 

[95wagon]

While not on a G8, have used ARH headers on a lot of stuff with good success.
Had two cars basically identical other than one having headers with junk collectors.
There was a difference, that was verified when the headers were tried on the other.
While not exotic merge collectors, ARH spikes and collector pinch do appear to make a difference.