1985 Grand Marquis 2-Door

[gadget73]

Ford only ever made 2 vehicles, the Mustang and the F150. If you want to work on anything else, you have to get creative and rob parts from those bins.

[Rodentkiller]

You may need to make custom excaust pipes for your car just keep it in mind.

[sluggish91]

https://www.amazon.ca/gp/aw/d/B000CI...K6Y9EEQB&psc=1

Does this seem right?

Yes. I have a Summit H-pipe, but the BBK one will work the same. You WILL have to extend the O2 sensors. I have a CFI car with only one O2, so I had to plug the driver side O2 bung and extend the one wire O2 sensor on the passenger side.

[sluggish91]

You may need to make custom excaust pipes for your car just keep it in mind.

This is true for those wanting to run tailpipes. I just dumped the exhaust at the mufflers before the diff.

[sluggish91]

Pictured is a MAC 1 5/8th equal length I had from another project (a basic standard aftermarket short tube header) lined up next to a stock 1985 h-pipe. Notice how the collector on the header is much larger in diameter, and won't seal or seat into the stock h-pipe properly. Also, notice how the header and h-pipe hardware will not line up, as the header hardware is spaced out a bit wider, and the h-pipe hardware is narrower, as it's intended for exhaust manifolds, and not an exhaust header.

My dad's 1991 Grand Marquis also had exhaust manifolds, and the same h-pipe (except with four catalytic converters instead of two), so I'm inclined to say this will be the case with all MGM Box chassis vehicles.

[Giraffe]

View from underneath. They torched the h-pipe at the bends to tuck it up as much as possible. Because I used a Mustang H-pipe, it doesn't line up with the crossmember. In this picture they are still in the process of getting everything welded completely. You can see the stock hanger on the right and a hanger they used on the left.
[ATTACH=CONFIG]53346[/ATTACH]
BBK Headers Passenger Side
[ATTACH=CONFIG]53344[/ATTACH]
BBK Headers Driver Sider
[ATTACH=CONFIG]53345[/ATTACH]
Side View of where the Mustang H-pipe hangs
[ATTACH=CONFIG]53342[/ATTACH]
Another lower side view (theres the dark spot above the h-pipe bend where they torched it)
[ATTACH=CONFIG]53343[/ATTACH]

I guess if I really wanted to, I could get a longer piece of pipe to widen out the h-pipe and tuck it under with the crossmember humps. Only time will tell if that is necessary.
As for the results of this mod, I couldn't be more satisfied. The sound is just..... . . . . . . . . . . . . . . . . . . . . . . delightful. Really changed the entire dynamic of the car. I have to say it sounds on par, if not better than my Mustang. This is exactly what I was looking for. Sounds damn good. Now the mean sound is going to match the mean look. Still slow though!

I have a couple questions for you:

1. You're still running the stock LoPo heads at the moment?
2. If so, did you experience much loss of torque with the larger diameter exhaust? I have a complete exhaust system ready to go in my car but have been hesitating at pulling the trigger on the install because of things I've read on here regarding loss of low end torque with the larger diameter exhaust.

My car is currently a 2.73 non-locker as well. However, I do have a 28-spline locker I grabbed from a junked '94 Mustang GT along with some 3.27 gears that will be going in. If that's enough to compensate for lower torque with a 2.5" exhaust then I'll probably go ahead and install everything so I can get it out of my trunk and garage.

Yes. I have a Summit H-pipe, but the BBK one will work the same. You WILL have to extend the O2 sensors. I have a CFI car with only one O2, so I had to plug the driver side O2 bung and extend the one wire O2 sensor on the passenger side.

About how much did you have to extend the sensors?

[sluggish91]

1. You're still running the stock LoPo heads at the moment?

Yes, heads are stock LoPo heads.

2. If so, did you experience much loss of torque with the larger diameter exhaust?

I felt the loss of torque, even with a 3.55 gear. I was looking for a certain sound out of this car, so it was worth it for me.

About how much did you have to extend the sensors?

6-12in. on my one single wire 02

[Giraffe]

Yes, heads are stock LoPo heads.


I felt the loss of torque, even with a 3.55 gear. I was looking for a certain sound out of this car, so it was worth it for me.


6-12in. on my one single wire 02

Thanks for that info. I may go ahead and install the exhaust after we move. Nice car, by the way!

[sluggish91]

Thanks for that info. I may go ahead and install the exhaust after we move. Nice car, by the way!

Thank you, always a work in progress. I was in the same shoes as you, should I install or not? I had all my exhaust pieces ready to go already. Decided to just go ahead with the install and I was not disappointed. I mean, yea there is a loss of torque below 2000 rpm, but with only about 4300rpm of camshaft to work with, the loss is clearly evident. I'm sure if I had a cam with 1000 more rpm range, and maybe an intake manifold to match, it would make use of the extra tube diameter. Again, I really was just looking to make it sound cool, and it did that, so I'm happy.

[sluggish91]

If the transmission you have doesn't have the HI-REV governor, add it to your list.

The HI-REV governor is included in the Transgo AOD-HP kit.

I would go with a Weiand Stealth intake, if you don't yet have the performer.

What benefits would the Weiand have over the Edelbrock?

Weiand Stealth 8020WND
advertised operating range: idle-6800 RPM
"long, separated runners for bottom-end and mid-range power, plus a special runner design and larger plenum"
High Rise Design
Height: 4.970

Edelbrock Performer 2121
advertised operating range: idle-5500 RPM
"low-rise, dual-plane designs with patented runner tuning and a 180 degree firing order... boosts torque over a wide rpm range
Low Rise Design
Height: 4.120

Is this going to be a regularly driven rig, or a weekender?

Regularly driven but modified cars don't scare me if you know what I mean.

ditch the damn VS carb and go right for a 600 DP. MS, 3200+ stall converter and the 4.10 gear will make it fun to drive

I like the way you think.

[sluggish91]

I found some time this weekend to install some roller rockers I had laying around.

I was going to use them later this year on my pedestal mount aluminum heads but those aren't ready to go yet, so I figured another little mod would help overall. I really can't tell a difference from a performance standpoint from this part individually, but in conjunction with all the other tinkering I've done, it feels pretty solid.

These rockers are used but in good condition.

Ratio is unknown to me. I was able to use the stock pushrods and install without shims, so this leads me to believe they are a 1.6 ratio.

Still using the stock valve springs.


I pushed it as far as I ever have spinning up to 4500 rpm in 1st manually shifting the AOD. It feels pretty cool, and kinda like it wants to keep pulling. This motivates me to get the Shift Kit and High Rev Gov. installed. I need a higher stall converter. Wanting to go non-lockup and run an aftermarket transmission cooler. AOD is getting some mods soon.

[sluggish91]

Transmission Cooler Install

Howdy friends, hope all my Grand Marquis friends are doing well and staying healthy.
I installed an aftermarket transmission cooler in-line with the factory cooler today.
Here's how I went about it.

I acquired a HAYDEN PN:512 "high performance transmission cooler".
Measurements are 7.5" x 12.5" x 0.725"


I also needed a 1/4" fitting for the stock radiator outlet.


I discovered that on a Ford AOD transmission the top line going to the upper port on the radiator flows in towards the radiator and is the hot line. The lower port on the radiator flows out and is the cold line. I left the top line alone. I disconnected the lower line with an 11/16ths wrench.


A bit of fluid came out, but that's natural right...


Some ARP Thread Sealer and we're on...


The line coming out of the radiator goes to the top of the cooler.
The lower cooler lines goes back into the stock return line.
The stock return line has a female fitting with a hose barb at the end of it, permanently temporary I guess.


Mounted on the radiator via the little zip tie things that come with the cooler.
My electric fan was impeding me from getting more than two on there, but it should be alright.
Also, this picture is upside down.



Just wanted to share my new found knowledge, as this is my first Automatic car and I'm learning some cool new things.

[87gtVIC]

Cool. Not that it matters much... I believe from the factory ford went through the auxiliary tranny cooler first then the internal radiator cooler.


Good to have a cooler.

[gadget73]

factory cooler on my 86 connects out of the lower port on the radiator.

[87gtVIC]

factory cooler on my 86 connects out of the lower port on the radiator.

All those year I had it installed backwards then. hmm. I had the special factory bent line to just in the upper hole looping to the aux cooler. oops. All torn out now though. Pondering re purposing the tranny cooler as an additional PS cooler.