[quote=OrangeProwler]Not my post but, here is where I found this post. I hope this helps you.

https://www.dakota-durango.com/threads/4-7-headers.476373/ and Post #6.

That's funny, I was gonna investigate that forum today myself! That thread was a good read, even with bickering that started. I guess how deep we dig will depend on my girlfriend's income tax return this year! and YES I say HER return! It's HER truck! I'm still trying to squirrel enough cash away for a flywheel and clutch so I can move forward on the 5.9 magnum swap I have planned for my 83 D150. She eventually wants to make "Beth" her toy truck and get another for daily duties. If you've ever watched Yellowstone, you'll get the Beth nickname.

I'm one of those "changed to headers but did not change the Y-pipe and change to the 3" tubing", and I'm one of those that report no significant changes. So like said earlier, I can only report my results. Given the post about results with headers/Y-pipe/3" tubing, sounds like he has a lot more experience with the 4.7V8 than I have experienced.

What I do know of engines is all 4-strokes come down to breathing, and breathing at the right RPM range to realize real performance result. Headers, exhausts, have much less to do with sound and everything to do with creating power at the right RPM range for gains the driver can feel and use. If the changes make more power, at higher RPM, and its a RPM range you don't use, no gains. If the changes make more power, especially more torque where a driver can really use the gains, that's worth the efforts. The 4.7, even the 4.7HO in stock form has a sagging torque curve with a power peak at about 3,300 RPM. If the right changes flatten out that sagging torque curve or even make it a humped torque curve shape, thats gains a driver can use and feel.

This is the kind of info I'm after. I haven't priced out the upgrade Y pipe, but I'll guess it's not cheap either. We aren't building a race truck, just looking to upgrade to make a more fun to drive truck. We already ditched the factory muffler with a 2.5" Dynomax Super Turbo muffler. That gave her some much needed attitude, and my girlfriend loves the sound! I was pleased with the bark it has, even as a single exhaust still. I guess I'm still used to the sound of them on tired, smogger era 318s!

I just ignore the bickering on there. AirRam (Nick) was the guy sold parts back in the day try to help get more performance out of the 4.7L V8. He had a 2002 Quad Cab with a 4.7L for a while. I put a Y Pipe on my 4.7L Dakota but, I think I also had an ASP Underdrive pulley installed as well around the same time. I think both made a difference but, the pulley made more of a difference. Just a point of reference that pulley is no longer made and hasn't been for years. I also took off my clutch fan as well and ran the electric fan on the truck at the time. Honestly, the manifolds on the 4.7L are okay but, headers are nice especially if you can upgrade the exhaust manifold bolts that love to break then cause an exhaust leak.

Those "tired old smogger era 318s" are engines worth building. A good basic engine, with the right intake, carb, pistons, cam, heads and exhaust can easily make 350 HP in pump gas.

The 318 and the 5.2 Magnum are often overlooked as simply gramdma Plymouth car engines. But with the right combo of parts they can make real good power and ready to rev.

Oh I'm not bagging on those old 318s, they're great little workhorses. I swapped in headers and 2.5" duals on my old 77 W200 and they woke up the truck nicely. When it came time for new exhaust on Dad's 69 Dart (84 318 swapped in) the Super Turbos were my recommendation. 15 years later, Dad still comments that I made the right choice for him What shocked me when we put one on the Dakota was the bark it has compared to the old 318s. I can only attribute that to the higher compression ratio in the 4.7.

Ours has a hole on the drivers manifold just above the outlet flange. JB weld shut it up for almost a year. I rolled the dice and bought a Dorman manifold and new bolts. Once my 83 is back together and out of the shop, I'll tackle the manifold swap