Gibson makes quality products, but it may not sound as good as a magnaflow. You can check customer reviews and prices here: http://motorhaven.autoanything.com/exhausts-mufflers/20A50080A1.aspx

 

Dual exhausts are not needed on the 4.0. Gibson gets good reviews on another Ranger site that I visit, as does Magnaflow. Your least expensive approach would be to pick up a muffler that you like and have an exhaust shop put it on for you. Just make sure they do mandrel bends on the tubing, and you'll be set. Also, it will be all welded, no clamp joints to leak.

 

Try some flowmasters.

 

Gibson is excellent, I've had 3 of thier systems, awesome quality and nice deep rumble. The dual exhaust for the ranger isn't a true dual anyway, it splits off of the back of the cat. Duals are mainly for looks and a little more agressive sound.. The gibson I had on my last ranger was the dual sport, it had both pipes exciting behind the passenger side tire. I had it change to where they exited in front of the passenger side tire (lighting style). The flowmwster tends to be the loudest, but they drone inside the cab at different rpm's. Gibson gives you a nice deep throaty sound and rumble, but isn't loud inside the cab. Magnaflow and borla or great as well, but can be a little pricey.

 

True duals would give you a improvement, but you would really need headers to bring it out.

 

Headers don't do squat on the 4.0 sohc excpt lighten your wallet, they work better on the ohv 4.0. I had the jba headers, 500.00 bucks for nothing, also Rubydist who has posted above me has the headers and put it on the dyno, he gained nothing and lost some torque. The stock manifolds flow pretty nice on these engines. The best thing you can do for these engines to increase hp, is a bama engine programer and under drive pulley. A catback will give good sound, an intake will give you good sound and a little better throttle response, but the bama programer and udp's will get you about 15 more hp and 20 foot pounds. I had all this stuff on my ranger, the bama and udp's were the best mod for the money, the headers were a waste of money. My gibson sounded good and was worth the 300.00 bucks. It's hard to put a true dual exhaust on the ranger because it's illegal. Even with headers the exhaust still merges into one pipe at the cat and then duals off again after the cat for a legal system.

 

Opps, forgot I live where there is no emission testing! Though I suppose to work well you would have to do a second O2 sensor up (somehow).

 

Even if there is no emissions testing that doesn't matter. Your truck does its own emissions testing and if it fails your CEL will come on and you will fail the safety test if your light is on.

I would go for the headers. While it may be true that with the setup it is not ideal, the right headers should still offer improvement and they can nicely compliment future mods.

The benefits of true duals on a 4.0L are questionable at best. Dual exhausts offer the best bang for the buck on highly modded race engines. A single exhaust will smooth out certain parts of the powerband and make it less peaky and more consistent IF it is designed properly. Don't get me wrong, true duals do deliver more peak power, though in most cases not much. But they are easily oversized, they cool the exhaust more rapidly, and they have more surface area inside the pipe, all of which slow the exhaust down and limit power in certain parts of the powerband, namely the bottom end, and if they are too large, the midrange too. They can give a false impression of power, as can any mod, by being considerably louder than stock. Depending upon the muffler, they can also sound raspy, which lends to the effect.

Dual outlet mufflers are often louder than true duals with the same muffler setup. One muffler is louder than two. So a nice dual out muffler could give you a great sound. The single exhaust will be less raspy because the merging of the gases from both banks will absorb certain sound frequencies somewhat. It will mostly leave the deep rumble behind and filter out the white noise. The cats also filter mid to high frequency sounds, but the low frequencies tend to pass right through with less alteration.

Its your truck, and I encourage you to do what you want, but the modifications required to make a true dual exhaust system would be illegal and not easily implemented, and would possibly make it run poorly. I think the headers will help a little bit, and a catback would be a good idea, and if you wanted false duals, they do have an effect on sound.

 

The shortie headers don't help at all on a 4.0 sohc and will even loose some torque as evident from Rubydist dyno run. I had the shortie headers as well and they didn't do squat. The reason being that they did alot of flow testing with the factory exhaust manifolds to make them as efficent as possible on the newer ohc motors. Super six motorsports even commented on how well the factory manifolds flowed. However, I believe there would be some benifit to a set of long tube headers on these engines. Mac is the only company producing them at this time and thats for the 4.0 sohc in the mustang. Now people have reported good results with the shortie headers on the older 4.0 ohv motors, where the factory manifolds don't flow as well as they do on the sohc motors. I ended up taking the headers off of my truck because of lose of lowend torque. I wheel alot and lowend is important to me. So unless you try a set of long tubes, I wouldn't waste the 500.00 to 700.00 that the shortie jba headers cost. I was lucky, I only spent 400.00 as I got mine off of ebay, but that was 400.00 that could of been better spent else where.

 

Sorry, I keep thinking OHV 4.0 Hate to tell Bear River but in a 91 there are no sensors past the cat, so no fault code and ( bad ) we do not have real safety inspections, or any emission testing. So no fail for my truck . However I do not have headers as I think it would be to much of a pain to install in a air conditioned truck and I am too cheap to pay someone to do it. I am a Oldsmobile big block fan and learned a long time ago ( not via my wallet ) that relatively small tube headers and exhaust were the way to make useful power (on the street ) unless the whole package was done out for racing. If I remember right 1 7/8 ths headers into 2 -2 1/2 inch exhaust worked just great.That is for Olds 455's, not V6's in trucks.