1978 mustang new member

429MII

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Well....Got some stuff finished but not as much as I wanted...Anyway front suspension and a-arms are done so next is finalizing the engine mounts and building a trans mount, installing the subframe connectors ,reinforcing the torque boxes and rear leaf spring mounts, jabbing up some heavier shackles, cutting the rear floor and installing the fuel tank, installing a roll bar.....Just a few things to do lol....
Some of the welds I am re-doing even though the area got painted. I had some bad lighting and there is a couple of spots to grind off and re-do, but for the most part, while not super pretty, the penetration is good, and the plates only really needed tacking not full welding.
 

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2Blue2

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.Got some stuff finished but not as much as I wanted...
Looking good, 429MII
Granda ma always said "One thing done and that done well" when she talked about chores and tasks.

Happy Mothers Day Grandma!
 

429MII

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One thing became apparent for me about the build of this car from the start. I would need to do something about the fuel tank.

1) I don't like the filler on the side of the quarter, it looks goofy to me.
2) I don't like the fuel tank location on one side of the car mainly.
3) I don't like exhaust exit location which is usually forced to one side or dumped under the car because of fuel tank location.
4) I don't like the "shotgun straight out the back exhaust look that so many ford cars have.

To that end I am installing a 65 mustang fuel tank as previously mentioned. I mapped it out last night and have some interesting notes on the subject, but I'm off to work right now, so have to post later!
 

2Blue2

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I agree gas filler location sucks, stupid exhaust design for stang.


this aint a whole lot better either, but fun to see the ankle burner exhaust on a mutt2
MII_Side_0506.JPG
 

LILCBRA

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There have been a few who have done the same as what you're looking to do with the tank, it shouldn't be that big of a deal. And I know what you mean about dumping the exhaust under the car, I was more or less forced to do it myself. The Fox tank I installed is actually a little bit too wide, I had to pound a little bit of relief into the bottom corners to make sure I didn't have any kind of problems with the leaf springs hitting anywhere. They probably wouldn't have, but I wasn't going to chance it.

I once had a II that I had the exhaust turn and run out in front of the rear wheel. I pulled it off after a short time, didn't like how it sounded. And I've never been a fan of side pipes. I think they only look good on a few select cars, most of them being roadsters. I think if I could run my exhaust out the back somehow, I'd either want it turned down right behind the rear wheels (which I don't think would work), or tucked up under the body and turned down at the bumper. The slight drawback to that is the extra bends which also help cancel sound. I wouldn't want to change the sound of my car, but I sure wouldn't complain about it being a little quieter!! The drawback of turning down under the rear seat.....
 

429MII

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"behind the rear tires would be ideal but hard to do with leaf springs and m2 gas tank."


Yes exactly what I was thinking of where I want it to dump. It will take some creative metal work to make it possible, but it will work I think.
 
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429MII

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So in doing my measurements for the tank, I have discovered a few things.

1) The 65 mustang fuel tank filler is NOT centered in the tank.... curious.... I always imagined it was centered.
2) The rear centre brace at the back panel inner structure is also NOT centered. also curious. I always imagined it would be.

The 65 tank is 33" across by 24" wide including flanges.
The rear hatch floor is about 43 between the wheel wells to 49 inches wide at the back and about 33 inches from where the back seat goes.

This allows for plenty of room, and a fair bit on either side. The fuel filler is offset to the drivers side by 1.5 " and the brace not as much, meaning my net shift to the drivers side is only about 3/4" to centre the fuel tank opening in the rear panel. This however permits the other plan for the rear area as I mention in a minute.

Of course I gould move the filler neck, but I am trying to not have to do that.

I ALSO wanted to mount a group 27 battery in the right rear corner (pass side). It looks like that may also fit with an inch and a bit to spare. I will "sink it" into the floor by however much is possible without interfering with the rear spring hangers. I haven't done a thorough investigation yet to see how that plans out yet.
Pictures of the hatch floor alterations will follow once I mark it out with felt pen prior to cutting.
 

extra_stout

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My thoughts go into this direction:
t-1977-mustang-ii-2007_0201exhaustnewiimustang0004.jpg


t-1977-mustang-ii-2007_0201exhaustnewiimustang0006.jpg


Thats an idea of another forum... There is - similar to the stock configuration - a big dual inlet / dual outlet muffler beside the fuel tank.
I like this idea, because it should still be easy to get the driveshaft out, with the additional hanger mounted to the trans crossmember you can use flex pipe in front and it is almost a straight design. From the sound perspective: I only like to use absorption mufflers and with a big dual in / dual out filled with glass wool at this postion of the muffler the sound should be deep and not as rough as a true dual system, but rougher than an h-pipe.
Also from weight distribution perspective... it helps.
Lets se what i think of this idea when is start building this...
 
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74stang2togo

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I ran an H-pipe from my headers to a pair of these: https://www.summitracing.com/parts/wlk-17676/overview/ , then I ran a pair of 90-degree pipes from the outlets to the tips. I've been giving serious thought to replacing the 90s with 120-degree bends to move the exit further back.

All of the cool-factor of side pipes without the ankle-burning, and zero interference with the gas tank, and none of the deafening resonance of dumps.

That said, my previous solution was a fuel cell in the trunk so I could run duals all the way out.

Here's the result:

View: https://www.youtube.com/watch?v=jwODyOvPR5s
 
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429MII

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I think I have it figured out now. It will work with two 2.5 inch pipes up the centre and over the axle and exiting on the outside of the leaf spring dumping down at the back. Will require some cutting and welding but it will work. Mufflers should sit where the rear seat bottoms are.
 
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LILCBRA

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Mufflers fit well there, that's exactly where mine sit. It works well because of the floor raising slightly and is just about the right length needed for mufflers. :nice:
 

429MII

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Took the leap of no return and cut out my rust free trunk.....eep....
had some flanges bent up to weld in to allow the tank to mount properly.
Will need to build a new rear frame brace as the one thats there is a weird shape and in the way,
Still looks pretty straightforward, but I want to get the brace in before I cut the rest out just in case.
20190515_182034.jpg
20190515_182059.jpg
20190515_182155.jpg
20190515_193348.jpg
 

429MII

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Ok... so I cut out the rear crossmember/fuel tank hanger, and removed the rear bumper. I added a 3x3 .120 wall rear crossmember across the back of the two frame rail stubs. pictures will follow later today.
Man, I gotta say, the rear bumper assembly is HEAVY.,,lol a one person job removing that beast is not fun...

Today I will continue with cutting out all the other stuff I don't need under the floor, and final trim on the hole before mounting the new tank mount flange. I had the flanges tabbed up in 16 gauge so they are pretty tough, and the rear floor appears to be heavy gauge as well so being a full perimeter mount should be really strong.
I probably didn't need the added rear crossmember, since the primary function of the old one was to support the fuel tank, but the rear crossmember will tie the frame together nicely at the back, and reinforce the rear spring hangers at the same time, and I like to over engineer everything anyway.
I am considering boxing the rear frame stubs also, we will see once I get a better look.I am also going to reinforce the upper leaf spring mounts as they look cheezy (sub-standard) to me.
My goal is to get the fuel tank at least dropped in today. The battery box/mount fabrication will complete the rear hatch floor mods.

Oh yeah, all that "red" coloured stuff in the trunk pictures is not rust..this car is rust free..It is some kind of spray glue and insulation remnants.The strip of orange was some kind of tape. the other stuff in rear pictures is dirt. It will look better once I clean it up.

After the hatch floor is handled next comes the frame connectors installation.. which as I think about it ...will probably have to be done in combination with the trans mount set up and roll bar mounting. Since I don't have a roll bar, I better take a look at what is out there or have one made I guess.
So far i am still planning to use the factory rear seat, although if that proves impossible it won't be a big deal, as I probably would never put anyone back there anyhow..
 

429MII

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I don't know why the lip closest to the back seat looks crooked in the photo...it is level...but yeah that was a lot of sweat and metal particles to get to this point lol.
 

2Blue2

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Yeah the blue one is like what Im envisioning too. ( no cinder blocks for jack stands though, I've seen it go bad)
Is the pipe between the fender and tire at the exit? It all looks super tight.
The one on yellow lift looks hard to remove for trans work. I guess its just tacked at the muffler. Is a pretty exhaust system. ;)

If you fill that 3x3 at the back with concrete your car will do better wheelies.:rolleyes::D

cc6ee55542d081edc8e64efe5c742eb3--wednesday-dirt-track.jpg
 

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