BlueMaxCougar

The Mark VIII is the same chassis as the Thunderbird/Cougar from 1989 to 1995.The chassis went to 96 or 97 with the Mark VIII.The only difference is the Mark VIII came with air ride suspension, and some of the outer sheet metal and interior is different.

gofastwclass

iTrader: (2)

My original plan was to build a Mark VIII but the Thunderbird fell into my lap for a price I couldn’t refuse.

As far as I'm aware, my car is the only swap on this (MN12) chassis. I know a lot of people who want to or have started, but I'm not aware of any that have been completed. It's an easy swap for an experienced fabricator, but there are a lot of pitfalls.


The Mark VIII chassis actually goes to 1998 and the Thunderbird / Cougars stopped in 1997. Plus what you listed, our Mark VIII cousin also has aluminum lower control arms in the rear, an aluminum differential case, aluminum hood and an aluminum driveshaft.


I’ve thought seriously about replacing this car with a Mark VIII, but the Mark VIII is the same chassis. Since they are the same chassis and I can only go one year newer, I’m afraid I’ll have the same chassis problems. My issue is this chassis has what I perceive to be some minor but annoying design flaws that keep it from being really cool.

I really like the looks and if I find a clean Mark VIII for the right price I may do another build thread… but lately my main focus has been my 1961 Impala conversion.

Moose_of_Death

First of all, thank you for replying.

1. Mine's a 1994, OBDI, yay or something.

2. I've already got most of the dealer manual stuff, plus the large map-sized wiring schematic. It's a bit daunting.

3. I'm seriously considering some kind, ANY kind of swap into this car, whether it be an LS engine or even a Ford 300-6 cylinder, I'm simply that pissed off at the ridiculous engine in this thing, and the cost of doing mods. I've got a spare, low-mile DOHC on an engine stand that's supposed to go into this car, and I'm looking at spending $400 simply on a timing set...yeah, thanks, all done. I've got the intake manifold off, valve covers, timing cover, hell, there's something like 100-plus bolts loose right now, without digging further into the car. Once you also take into account all the things wrong with the DOHC engine into this car...I'm really curious as to what kind of idiot spends money attempting to mod one of these engines.

4. The Mark 8 has some advantages over the T-bird/Cougar:
A. What appears to be a 3/8th's fuel line
B. smaller wheel openings, which doesn't make it as difficult to find a tire/wheel combo to fill the wheelwell...like on those other cars.
C. The car appears to be somewhat better constructed...okay, not that much better constructed, but maybe slightly better constructed.
D. I think the 8 looks better. The Bird and Cougar just look....odd.
E. Well, I already own a Mark 8. That's good, right?

I actually had two 5.3 truck engines in the garage at one point...but sold them, as they didn't have accessories or anything, and was put off by having to fabricate freaking everything to install one.

The easy route would be to just simply buy something Chevrolet-ish which would make a swap that much easier, or even running a regular SBC that much easier, which I can make work. The issue is that there really isn't anything made by Chebby that I like from a vehicle platform standpoint, so here we are.

gofastwclass

iTrader: (2)

See topic 3 below.

1. What the car currently is doesn't matter. Most of the vehicle electronics stayed in place, the engine electronics ended up in the bin.

2. I understand the wiring can be daunting if you've never done it. Just take your time.

3. I'm a GM guy and I looked into a DOHC 4.6 / 5.4 swap and decided the power, economy and parts availability weren't there. Upgrade cost placed that completely out of reach.

4-A. I still believe the Mark VIII's are 5/16" fuel line - at least the ones I measured in the salvage yard. I thought that would be an easy upgrade but I was wrong. Maybe the LSC cars.

4-B. I'm not a wheel guy. I'm actually running Mark VIII wheels and brakes. I wanted a stock wheel to keep the sleeper theme.

4-C. I'm not sure about construction although the interior is nicer and you get more gadgets on the dash.

4-D. I do prefer the lines of the Mark VIII, especially the 1997 -1998 LSC cars. That is what I was originally looking for when I found this car for an unreasonably good deal. If I was doing it again I would try to find a 1997 or 1998 Mark VIII.

4-E. You're one step ahead if you already own the car.

From an accessory drive standpoint, I think I could get a 2007 - 2013 Corvette drive setup to work in one of these cars with little drama. I'm not sure about the low mount AC, but I think the measurements work out in favor of everything else. If I were doing it over with current money, I would buy an accessory drive rather than build one. I was on a very tight budget with this car and building things was the only way to stay on track. My current project has a much looser budget - but it's a larger project.

I wish you well whatever direction you go.

Moose_of_Death

I was seriously thinking of trying to scare up a take-out early Camaro/Firebird 5.7 (1998-2002), and starting with that, even if it's an automatic. The intake's already a good height, the belt-drive brackets are close...

gofastwclass

iTrader: (2)

That is a good thought as well. I've often thought of purchasing a complete wrecked vehicle for the drivetrain and selling what I don't use.

gofastwclass

iTrader: (2)

Well the Thunderbird daily is still kicking.

Last week I replaced the 165° thermostat with a 187° unit and Saturday I bought four new tires just in time for the snow. I would have used a 192° thermostat if I had one on the shelf, (thought I did but I didn't). I discovered last winter the 165° thermostat won't allow the engine to stay hot driving down the highway on a 30 degree day. Something easy to forget until it gets cold outside. As such, I basically didn't have heat as long as the car was moving and barely had heat stopped. According to HP Tuners, the coolant temperature was hovering around 169-171°. Placing cardboard in front of the radiator only made the stopped temperature rise but did nothing for rolling.

My original lower radiator hose was two random hoses I found coupled together with a bit of tubing. Quick, cheap, dirty, functional and terribly ugly. Earlier this week I made a tube from mandrel bent pipe that was a better looking and more solid / reliable design. This allowed me to save money by only buying one hose consisting of two 90° bends on my custom metal radiator tube.

The hose I used is Autozone #71303 which is 1.5" inside diameter, has two 90° bends and two 45° bends and cost about $15. I cut two 90° bends from this and attached them to the ends of the tube.

For tubing, I had some 1.5" mandrel bent tube I have been using for similar projects. I cut it to 90°, extended the legs the proper length and attached it to the car using the previously mentioned cut hose on each side.








Now HP Tuners shows my coolant temperature in the 190-192° range rolling so I have heat even though the outside temp was -1.

ls1nova71

iTrader: (4)

Hey, just an fyi, -1* is nothing to about. Its more like This **** sucks.....

gofastwclass

iTrader: (2)

I completely agree, I'm just happy to have heat again! Before I had to drive with my coat, hat and gloves on - and I was still cold!