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Discussion Starter #1
im sure its been done on a bronco, but does anyone have any pics of the driver side? i want to run the pipe strait back but got the driveline/tranny linkage to deal with, anyone got any ideas/pics of this. any help would be great.
Thanks
 

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Duals are completely pointless unless you are running a serious motor, that being said, i love mine even on a stock motor, and i always like the way duals sound...










Full length headers, true dual 2.5", single chamber race mufflers out before the rear tire.

Exhaust is routed under the frame behind the radius arm brackets, then routed up to the mufflers (on the outside of the frame, both sides) then dumped out the side before the rear tire. It is only about 1/4" lower than the xfer case skid plate.

The only time I ever have a problem with fumes is at a stop with all 3 windows down. If the back is up, i never have a problem.
 

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Discussion Starter #3
nice, i wonder if i could make room in the tranny cross member for a 3" pipe:popc1:
yeah i hear you on the motor, been puting some work in on it.
specs are... 408W, forged crank, pistons, rods (H beam), vic jr, 780 double pumper, trickflow 225cc high ports(on the way :rockon). should be a lot of fun soon. been running some tricked out dooe heads for awhile.
Thanks for the pics
 

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What are you trying to do with this thing? Drag race it? 225cc heads? Victor Jr? 3" dual exhaust? Your going to have ZERO bottom end. For a truck, something more along the lines of 185cc heads will do well and if you abosolutely just have to have true duals, dont go any bigger than 2" pipe. You know the Victor Jr doesn't start making power until 3500RPM, right?

Hey, if putting a high RPM monster in a heavy truck is your thing, sweet. I just don't see it being very fun to drive.
 

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Discussion Starter #5
What are you trying to do with this thing? Drag race it? 225cc heads? Victor Jr? 3" dual exhaust? Your going to have ZERO bottom end. For a truck, something more along the lines of 185cc heads will do well and if you abosolutely just have to have true duals, dont go any bigger than 2" pipe. You know the Victor Jr doesn't start making power until 3500RPM, right?

Hey, if putting a high RPM monster in a heavy truck is your thing, sweet. I just don't see it being very fun to drive.

why does everyone say this:banghead

look at a GM LS7 motor, 90mm throttle body, 270cc heads......STOCK and made 434ft. lbs of trq at 2800rpms.
i would go bigger on the heads and intake if i could afford it. :rockon
 

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why does everyone say this:banghead

look at a GM LS7 motor, 90mm throttle body, 270cc heads......STOCK and made 434ft. lbs of trq at 2800rpms.
i would go bigger on the heads and intake if i could afford it. :rockon

I think(?) the reason you hear that so often is because in most cases it's true.
My particular Bronco is my DD AND my go get/haul stuff truck. It's got a C6, 3.55 gears and seldom see's more than 2500 RPM. At 55MPH, I'm turning less than 2400 and cruising just fine. What the heck do I care how much torque my motor is making @3000 RPM, how much HP it's got @5500, or even how much air my heads will flow @ .500 valve lift?..... none of that is the least bit revelant to the task at hand, 'specialy if it's loaded or pulling a trailer of some sort....which a lot of trucks are called on to do.
What I (and most owners) need is more torque down on the other end, so's to get these heavy-ass*d things rolling with as little strain as possable.

I aint knocking the Bronco hot rodders. Hot rodding and racing can be a lot of fun.
Just saying.

DGW
 

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why does everyone say this:banghead

look at a GM LS7 motor, 90mm throttle body, 270cc heads......STOCK and made 434ft. lbs of trq at 2800rpms.
i would go bigger on the heads and intake if i could afford it. :rockon
So, I looked up the LS series engines. You know those were originally designed for the Corvette, right? That'd be like putting a Cobra engine under the hood. Yeah, it'd make a lot of noise and power, but not in any RPM range that would useful.

I don't know what your talking about 484 LB-FT at 2800RPM. The number I saw was 470 LB-FT at 4800 RPM. I have no idea how you drive your truck, but mine almost never sees RPM that high.

For a large truck such as the Bronco, you want high air velocity, not massive flow numbers. Well if you want to do anything truck like with it. If your looking for a Bronco version of the Lightning your on the right track.
 

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For a 408 I would definitely use something larger than 2" pipes. My dual setup (on a presently stock 5.0 with mustang headers) runs along the frame similar to the original until after the transfer case and then the drivers side bends underneath the rear drive shaft to the drivers side. Mufflers are mounted side by side as in a car and tailpipes turn out behind the rear tires, mimicing the original tailpipe just symmetrical on each side. This is all in 2.25" pipe without mandrel bends.

Now for a engine like you plan I would of course go with mandrel bends and put just a little more thought in the system than what I described above. It works very well for me and I saw a definite hp and tq increase from idle to redline based on stp meter. Fuel mileage went up about 3 mpg too. Of course I have 33s, 4:11 gears, and AOD and see 3-3500rpms just about every day in my commute to work. The 3500 rpms isn't in OD, but perhaps 1st or 2nd. I am not driving illegally and can't figure how some people on here commute to and fro without doing the same.

Let me know how your build turns out. I have a set of GT40X heads (about 185cc) for my 351 swap. I am still "gathering" a few things and debating on swapping the stock shortblock in or perhaps stroking to 393 with a full rebuild. This will be lots more money for me as I will stay fuel injected and the second will definitely require mass air conversion. $$$$$$$$

tim

ETA: I am not sure if you are talking about tailpipes straight out the back or the exhaust. The exhaust won't work that way, as discussed above and I would caution against tailpipes straight out the back if you play offroad much at all. They will get bent underneath and destroyed in my observations. ymmv
 

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I dont know, i have had this discussion with some builders, and all seem to think that pulling a truck 5.0L out and replacing it with a Mustang motor will work a lot better. I know a lot of Chevy guys running 400-500hp small blocks, and their trucks are working real well. I used to be a bigger believer in the build a low rpm motor, but after seeing tall gears, big tires, and high rpms on the tach, I am thinking that for a dialy driver or rock crawling, low rpms might work. But if you do trails, mud, etc, high rpm motors seem to be in the trucks that work the best. My opinion anyway.
 

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Discussion Starter #10
SomeDude451- carcraft dynoed a ls7, thats where i got the # with 408 cubes thats big block size, why would you put small block size heads on it?

TS 90F150- you can get a 3.85 stroke crank off of summit for under $300, and use the stock rods, bore it 30 over, new pistons.... it would be a cheep 393. check www.sbftech.com they have a ton of info on these.:rockon

RRRAAAYYY2- your right, high rpm motor are in the trucks that work the best. you can always run a bigger gear.
 

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I would argue that duals are not needed even for a serious engine when a more practical 3" single exhaust will flow more than you need.
For any motor that gets driven on a daily basis, and isn't completely balanced, blueprinted, tuned 100% perfectly and running equal length tuned headers a single 3" will do just fine.

Where you really start to see some gains is on an application that is running equal length tuned headers into duals with an x-pipe. even then you are only getting gains from the scavenging effect and reduced pumping losses.

A race motor is what i would consider a "serious motor".:toothless

IIRC, nascar only uses single exit exhaust on tracks that have DB restrictions, they use those boom tubes right?
 

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I dont know, i have had this discussion with some builders, and all seem to think that pulling a truck 5.0L out and replacing it with a Mustang motor will work a lot better. I know a lot of Chevy guys running 400-500hp small blocks, and their trucks are working real well. I used to be a bigger believer in the build a low rpm motor, but after seeing tall gears, big tires, and high rpms on the tach, I am thinking that for a dialy driver or rock crawling, low rpms might work. But if you do trails, mud, etc, high rpm motors seem to be in the trucks that work the best. My opinion anyway.
We have a winner here folks!
The only correct answer to the question of "best" is.... It depends.

DGW
 

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For any motor that gets driven on a daily basis, and isn't completely balanced, blueprinted, tuned 100% perfectly and running equal length tuned headers a single 3" will do just fine.

Where you really start to see some gains is on an application that is running equal length tuned headers into duals with an x-pipe. even then you are only getting gains from the scavenging effect and reduced pumping losses.

A race motor is what i would consider a "serious motor".:toothless
well ahem... the first thing alot of people do to get more performance out of their vehicles is to free up the exhaust... by 1) installing headers 2) installing a higher flowing cat {or eliminating entirely} 3) performance mufflers {maybe even cutouts} 4) going to a bigger sized exhaust OR going to dual exhaust... you dont have to have a balanced blueprinted yada yada motor to benefit from these mods... certainly the more work you have into the motor the more you will benefit from the change to duals... and certainly an x pipe will allow you to squeeze a few more hp out of the combination...
my 01 Trans Am is a DD and Id love to put true duals on it if I had the room... it doesnt have a dual to single to dual because thats all it needs, its done for room, for emissions, cost and probably a few more reasons...


alot of people who have purpose built engines for work (towing or hauling), for better gas mileage, off roading might have a bone to pick with you about your definition of "serious motors"...

Im going to put dual exhaust on my bronco (reason i found this post for pics) because thats what I have from the donor f150... I was lookin to see whats been done, but I dont want to go under the frame... Ill cross over the drivers side and run them out right before the rear tire... I was wondering about maybe dumping right after the rear axle, but I think the exhaust should exit outside the "cabin" just in case the fumes come inside...
 

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if you want duals then run a single and get a dual exit muffler. Duals on a bronco are pointless and more expensive for no gains. the point of duals is the have the exhaust exit as fast as possible. with the amount of bends needed to get around everything you are defeating the purpose. There is a reason why we keep saying single because it works and is proven.

also your F150 setup is different and will probably requireing some hack work to get to fit.
 

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I personally like the looks of duals on each side behind the rear wheel. But, being into rocks more than mud, I know first hand they get the shit kicked out em back there. I do like this: run them out the rocker panel. Sweet!
 

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I have true duals that exit like the factory pipes, they are 2.5 inch from the manifolds back to some magnaflows and out. However the drivers side exhaust crosses under the trans bellhousing, then along the right side of the truck till it crosses back over above the rear driveshaft. With this configuration I'd just do a single 3" if I was redoing the exhaust.
 

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I personally like the looks of duals on each side behind the rear wheel. But, being into rocks more than mud, I know first hand they get the shit kicked out em back there. I do like this: run them out the rocker panel. Sweet!
I like the way this looks. This is what I was planning on doing with mine, when I do my true dual system, but I might use rectangular tips instead of just the round exit
 
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