Dual Exhaust Idea

[Bulletproof250]

I was adjusting the doors on the truck the other day, with the fenders off I noticed that the header flanges are actually above the frame. Yes, not a bunch, but it did get me to thinking how I might get the exhaust tubing, up and over the front portion of the frame, before the firewall and Cab-Mount. This would allow for running the exhaust outside of the frame on each side, and for me ending at the cab corner or just after it. I did search the forum, looking for other dual exhaust systems and wondered who else might have considered this approach, and if they did, were there any pictures. I imagine that a set of SBF/302/Mustang, Shorty headers may gain me a little more space above the frame to make the bend out. Yes, if flow is my main HP Gain this would not help, but until I'm running 400HP+ I doubt this is too much of an impact.

https://lh3.googleusercontent.com/uqqSY9lakx94VeDWf_qYcnTBzdGCm3AM2D2w4QSLVB1wsckpXF6YQacuyjq4vnAFGqAkrRMG7KJNuf85_exomf2Fle1XFE90cJtvN7oHkyOn4B5XeccJHULT1wPGQ_4zIeoOazKi6DQ=w600-h315-p-k

[kramttocs]

Can't say I've seen them on a Bullnose but Fender Exit headers are common for the earlier gen trucks.

[Bulletproof250]

Can't say I've seen them on a Bullnose but Fender Exit headers are common for the earlier gen trucks.

Thanks Scott, I'll search a bit for ideas on the earlier models.

[BLES]

Like this?

There would be plenty of room to run one pipe, but might take some creativity to make it happen. This is four 2" pipes exiting over the frame in that area, to run down the outside of the frame.

[ArdWrknTrk]

Fender exit headers are a thing but I don't know if I'd want them close enough to the floor to go over your nerf steps.

They will definitely get the floor hot over there.

Are you thinking no mufflers at all???

Because there's certainly not any room behind the rockers, and you have the steps...

[Bulletproof250]

Fender exit headers are a thing but I don't know if I'd want them close enough to the floor to go over your nerf steps.

They will definitely get the floor hot over there.

Are you thinking no mufflers at all???

Because there's certainly not any room behind the rockers, and you have the steps...

Thanks for the inputs,

Although the Nerf Steps are there, they are quite a bit lower than the frame. The frame rail is actually about the centerline of the tubes diameter and I don't see a problem with those. As for mufflers, I thought of this too when I was installing a new Thrush muffler on the truck and it seemed like it could be rather tucked up there under the floor. That being the case, I do have some small concerns about the heat in the floor, or behind the rocker and some fabricated aluminum heat shields over those sections, may be the way to mitigate some excessive heat.

I looked into "over the Frame" headers and confirmed this was way outside of the budget I had for the project. Also I plan to go with a larger tire size eventually, with not too much lift, and the size of 4 tubes running on the inner-corner of the fender well, isn't encouraging when regarding tire-clearance.

I guess we'll see, I pulled the trigger on some "Cheap" (<$150) Shorty-302 headers and I'll see how it looks, worst case I could send 'em back and abort the mission. I'll do my best to remember and take lots of Pics.

What the sound?

Any opinions on mufflers? I love the deep throaty sound but live in the suburbs, and do like my neighbors, I was thinking that 2½" Flowmaster 50 Delta flows, on each side were a nice middle ground, has anyone run these on a stock 351W? or have a preference, I could look at as well?

p.s. not a daily driver but I roll-out run early in the morning on the weekend

Thanks,

[Gary Lewis]

Thanks for the inputs,

Although the Nerf Steps are there, they are quite a bit lower than the frame. The frame rail is actually about the centerline of the tubes diameter and I don't see a problem with those. As for mufflers, I thought of this too when I was installing a new Thrush muffler on the truck and it seemed like it could be rather tucked up there under the floor. That being the case, I do have some small concerns about the heat in the floor, or behind the rocker and some fabricated aluminum heat shields over those sections, may be the way to mitigate some excessive heat.

I looked into "over the Frame" headers and confirmed this was way outside of the budget I had for the project. Also I plan to go with a larger tire size eventually, with not too much lift, and the size of 4 tubes running on the inner-corner of the fender well, isn't encouraging when regarding tire-clearance.

I guess we'll see, I pulled the trigger on some "Cheap" (<$150) Shorty-302 headers and I'll see how it looks, worst case I could send 'em back and abort the mission. I'll do my best to remember and take lots of Pics.

What the sound?

Any opinions on mufflers? I love the deep throaty sound but live in the suburbs, and do like my neighbors, I was thinking that 2½" Flowmaster 50 Delta flows, on each side were a nice middle ground, has anyone run these on a stock 351W? or have a preference, I could look at as well?

p.s. not a daily driver but I roll-out run early in the morning on the weekend

Thanks,

I like the sound from Magnaflow muffs better than that of the Flowmasters. I think they are deeper and quieter.

[ArdWrknTrk]

Thanks for the inputs,

Although the Nerf Steps are there, they are quite a bit lower than the frame. The frame rail is actually about the centerline of the tubes diameter and I don't see a problem with those. As for mufflers, I thought of this too when I was installing a new Thrush muffler on the truck and it seemed like it could be rather tucked up there under the floor. That being the case, I do have some small concerns about the heat in the floor, or behind the rocker and some fabricated aluminum heat shields over those sections, may be the way to mitigate some excessive heat.

I looked into "over the Frame" headers and confirmed this was way outside of the budget I had for the project. Also I plan to go with a larger tire size eventually, with not too much lift, and the size of 4 tubes running on the inner-corner of the fender well, isn't encouraging when regarding tire-clearance.

I guess we'll see, I pulled the trigger on some "Cheap" (<$150) Shorty-302 headers and I'll see how it looks, worst case I could send 'em back and abort the mission. I'll do my best to remember and take lots of Pics.

What the sound?

Any opinions on mufflers? I love the deep throaty sound but live in the suburbs, and do like my neighbors, I was thinking that 2½" Flowmaster 50 Delta flows, on each side were a nice middle ground, has anyone run these on a stock 351W? or have a preference, I could look at as well?

p.s. not a daily driver but I roll-out run early in the morning on the weekend

Thanks,

I'd definitely put heat shields in.

What I'm saying is the cab moves on the frame. The motor mounts allow the engine to torque in the frame.

And whatever exhaust you come up with is going to move with the engine.

Which might be going a different direction than the cab (depending on how crossed up you are, and how much torque you apply)

You're the one looking at it. I don't really know how much room you have.

But I much appreciate you being respectful of your neighbors

[85lebaront2]

I'd definitely put heat shields in.

What I'm saying is the cab moves on the frame. The motor mounts allow the engine to torque in the frame.

And whatever exhaust you come up with is going to move with the engine.

Which might be going a different direction than the cab (depending on how crossed up you are, and how much torque you apply)

You're the one looking at it. I don't really know how much room you have.

But I much appreciate you being respectful of your neighbors

Jim, you are probably old enough to remember the cruciform frame GM products, I know Gary is since he owned a W head Chevy. The exhaust on those went under the frame front kickup then followed the lines of the frame with the mufflers near the front and when the exhaust system got to the rear up and over the axle and straight or angled for exit. The hangers were behind the mufflers at the front so the weight of the mufflers pulled down on the pipes.

The real fun was watching a more powerful engine (348/409) twist on the flimsy mounts and bring the left side muffler up against the floor and nearly drag the right side on the ground.

The point here is the further out the pipes run, the greater the movement under load. Sometime I will see if I can do a good drawing of what I designed for my 1977 F150 when I put the 390 in it. Another option is to look at what Ford did with the mid 1984 - 1987 460s where it is dual to the muffler.

[Gary Lewis]

Jim, you are probably old enough to remember the cruciform frame GM products, I know Gary is since he owned a W head Chevy. The exhaust on those went under the frame front kickup then followed the lines of the frame with the mufflers near the front and when the exhaust system got to the rear up and over the axle and straight or angled for exit. The hangers were behind the mufflers at the front so the weight of the mufflers pulled down on the pipes.

The real fun was watching a more powerful engine (348/409) twist on the flimsy mounts and bring the left side muffler up against the floor and nearly drag the right side on the ground.

The point here is the further out the pipes run, the greater the movement under load. Sometime I will see if I can do a good drawing of what I designed for my 1977 F150 when I put the 390 in it. Another option is to look at what Ford did with the mid 1984 - 1987 460s where it is dual to the muffler.

Yup. My '58 Impala w/a 348 had huge torque and that caused two problems: the exhaust hitting the body if it wasn't positioned correctly, and the carrier bearing in the driveshaft, which I could lay over easily. On the other hand, I could come out on the clutch in first at idle, shift to second, and idle down the street at 550 RPM and 17 MPH. Dad's '60 283 wouldn't even think about moving in first at idle.