exhaust question, and then...

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Mar 14, 2005 | 02:58 AM

'70_f-100

Thread Starter

Junior User

Joined: Mar 2005

Posts: 74

Likes: 0

From: prescott valley, arizona

exhaust question, and then...

i have a '70 f-100, (hence my user name), w/a 390, a c-6 tranny, and and auxilliary tank that is now my primary. i chuncked the tank
behind the seat

into the scrap pile, and fixed the hole w/some good 'ol fabricating.
do to the incompetence of the "mechanics" that installed my 2.5" duals w/flowmasters

exiting at the bumper, i had to have the tranny rebuilt. they ran the driverside tubing about 1/2" from my oilpan and it sat pushed up next to my tranpan, which melted the gasket

and u know the rest.
my question is, i'm currenetly re-routing the exhaust, and would like some opinions on directional changes in the tubing. is mandrel-bent tubing truly the best way to change the direction of the tube, or are there any other designs? straight tubes are out of the question, because of the aux tank it would look horrible. i'm asking everyone for their opinion, and this one is mine!

my next and more important question is, what is the crossover's function in an exhuast system, and should it go in front of the mufflers or behind them, and at what distance would it be most effective?

Mar 15, 2005 | 01:00 AM

welldiver

Junior User

Joined: Apr 2003

Posts: 72

Likes: 0

From: Mtn. view CA

I've got a simular set up, my pipes exit out the back and i would'nt rerout it to the sides, just too loud for my taste. Mandrel bends should prevent any restictions that you would get from tying to bend it your self. Your h pipe should go in front of the mufflers, mine is directly behind the tranny under the drive line, space wise it fit best there and it ended up creating a safty loop jusy in case the drive line should fail. The crossover will eqalize the presure from the 2 banks that will help with low end tq and mellow the tone abit.

Mar 15, 2005 | 01:46 AM

"Beemer Nut"

Post Fiend

Joined: Dec 2003

Posts: 6,658

Likes: 4

From: "Islander"

Go to a X crossover vs a "H" design and install it as close to the headers as possible. You will feel the difference.

Carl....=o&o>....

Mar 15, 2005 | 10:38 AM

ceetwarrior

Cargo Master

Joined: Jul 2003

Posts: 2,328

Likes: 14

From: Colorado

I got my H pipe installed right in front of my mufflers. It couldn't be installed any further up due to the size of my NV4500. I like welldivers idea about the driveshaft loop, I guess it serves two purposes as it's right there at the slip yoke - nice!

Crossovers are about twice or three times more to get installed especially if you get a name brand one. Most good exhaust shops can install a H pipe for $25-40.

I had 'em do a custom H-pipe on mine. I have it flanged on both sides of my exhaust in case I need to take off on side of my exhaust - pretty trick.

Mar 15, 2005 | 10:47 AM

Unimog005

Elder User

Joined: Jul 2004

Posts: 920

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From: Westminster, Colorado

Man, I need to get to work.....I have a 390 in my 67 F-250 4x4.....with headers directly coupled to two cherry bombs....right under the cab......boy is it loud! I had wondered if the crossover worked as well for trucks as for cars.

Mar 15, 2005 | 12:05 PM

ceetwarrior

Cargo Master

Joined: Jul 2003

Posts: 2,328

Likes: 14

From: Colorado

The H-pipe made a huge difference! My exhaust was loud before and it cackled like most cherry bombs do.... but the H-pipe totally fixed it. It made the tone very deep and more consistant! Very well worth the dough.

Mar 15, 2005 | 03:02 PM

woods

Senior User

Joined: May 2004

Posts: 278

Likes: 0

I ran into the same issue with the drivers side pipe.

I originally walked the muffler guy through how I wanted the pipes routed and he tucked the drivers side next to the tranny. It was so tight to the tranny that I wouldn't have been able to pull the pan if I needed to
I went back the next day and told him that it was wrong and it had to be re routed or it would end up overheating my tranny and he agreed to re-route it.
The rework is not as clean and you could see the pipe when looking at the side of the truck but it works better.
I could get a couple pic's of the exhaust to you if you want something for reference.
Ken