View Full Version : Just a young Bird builder sharing his story

09-02-2014, 01:32 AM
Hello all, I'm Trevor (23) from Oklahoma, and I'm here to share my 1958 Squarebird Build with you. Also looking for some help from some of the other builders here.

I purchased my Squarebird from a guy who wasn't ready to tackle such a large project. When I first inspected the vehicle, the heads were off, and a large crack was apparent in the block. But the best news, NO RUST in the car. After some haggling, the car was mine, and I was following it home.

My thoughts for the car. Resto Mod. I know thats not a huge deal around here, but I love the idea of a DOHC 4.6L Cobra engine, large wheels, lowered stance, etc.

I build a lot of cars, and this one I will be keeping for myself.

After finding the Squarebird, I found a 1997 Mustang Cobra Donor Car that has a fresh built 4.6L DOHC in it.

My dad and I pulling the engine/transmission

A little dressing up, and it is about ready to go in.

I'm at a point now where I need to decide what to do with the suspension up front. Big brakes are on the list. My largest hurdle is crossmember, motor mounts, rear sump/pan. Has anyone done a modern swap here with any luck? I'm thinking of trying to fit possibly a tubular set up built for a fox body mustang into it.

Thank you all for the help!

09-02-2014, 03:22 AM
Trevor, thanks for posting your story on the acquisition of your '58 Squarebird and your plans for it. We have the best Tbird techies around on here, so I am sure they will be happy to advise and help you through this.

When I posted the Welcome to you in the New Members Welcoming Forum, I provided you with information regarding picture sizes. No bigger than 800x600 pixels. I see you are using photobucket. Please go into it and downsize your over sized pix in photobucket to 800x600 pixels. You might have to repost the links (or maybe not) after you do. You can see what is happening with your pix that are over the 800x600 limit. It is causing us to have to slide back and forth to see all the text you have posted. So please fix your picture size. Thank you and good luck with the work on your '58 and thanks for saving another rare '58 Squarebird.

09-02-2014, 03:33 AM
Hi Trevor, welcome to Squarebirds.org. I am not opposed to modernizing your classic Thunderbird BUT...

I'll start by saying, I love an all-aluminum 4-valve engine. The Cobra has a steel crank and four-bolt mains, but never forget that this engine is smaller than 300 cubic inches and you are putting it in a heavy car that begs for a lot of torque. I worked at Romeo Engine Plant when your engine was made. I also love EFI setups and power front disk brakes.

A word of serious caution: Do not fit a fox front end into the Thunderbird because it isn't strong enough. You can adapt to the motor mounts that are there.

The ride of a fox suspension on a Squarebird would suck compared to very long double 'A' arms already on a SB. These arms are so long, you won't need a spring compressor, and the ball joint suspension is MUCH stronger than McPherson struts.

Many of our members have Scarebird (yes, Scarebird) rotor brackets and S-10 calipers with Mustang 11" rotors. All of it bolts on directly without altering the geometry of the suspension.

Your challenge will be with the coil spring REAR suspension on a Ford nine inch axle. If you need help, ask lots of questions. -Dave

09-02-2014, 10:49 AM
Not sure why the pictures turned out so big. Spent a lot of time going through Photobucket sizing them accordingly.

For the mean time, I took them down until I can figure out why the sizing isn't coming through on the links.

09-02-2014, 12:33 PM
Hi Trevor, I see you figured Photobucket out and got the pix re-sized. Thanks! BTW, I think it is fantastic, that at 23 years young, you have already built a number of cars and that you are keeping this one for yourself. The '58 Squarebird had the smallest production numbers of all the Squarebirds. It was a big change for Ford going from the '55-'57 2 passenger Babybirds, to the larger, two seater Squarebird. Here is a website that might be of help to you regarding the '58 Squarebird.


Go through the various links and learn more about how your '58 was made. The reason why the '58 has rear coil springs instead of leaf springs is because Ford was planning on possibly installing air shocks/bags on the rear, as I recall, but changed their mind. Some people have done the modification to that rear and put leaf springs on instead.

Do you have the car registered on the Thunderbird Registry? John Rotella, also a member here, runs it and it is his attempt to record every crunched, parted out, still alive, in use Tbird he can find. Your Tbird might be listed in the Registry, and to find out, put the VIN # into his Registry and it will tell you if it has been registered in the past or not. Your Data Plate is on the drivers side door post and when you open your drivers door you should see the plate. Record the VIN # and that Data Plate information and that will tell you what that Tbird left that plant as.. Here is the link to the Tbird Registry.


Here is the breakdown of the Data Plate information.


I hope this info is helpful to you!

09-02-2014, 02:33 PM
I see the concern with the fox body front end. I'm going to a salvage yard today to get some deminsions on Mark VIII (came with a 4.6L) as well as Crown Vic front ends. Both have curb weights very close to a square bird, and would solve my steering and oil pan problems. Going to take a lot of pics to see if it's even worth the hassle of trying to French it in under my bird.

Just tossing around loose ideas at this point. I know a lot of f100 modifiers use those front ends.

09-02-2014, 06:19 PM

This might just fix the problem all together with out having to heavily modify anything.

09-03-2014, 11:04 AM
'58 Tbird weighs 3700 pounds
352 FE weighs 650 pounds
300 hp, 395 ft-lbs torque (gross)

'97 Mustang Cobra weighs 3200 pounds
4.6 engine weighs 400 pounds
305 hp, 300 ft-lbs torque (net)

With a weight savings of 250 pounds or more because you're probably not using the cast iron Cruise-o-matic either you get the Squarebird weight down to 3450 pounds which is in the range of some of the later Mustang Cobras.

I think the 4.6 will run pretty good.

As a comparison, for some reason, a 2014 Taurus SHO weighs 4400 pounds.

Joe Johnston
09-03-2014, 11:28 AM
Another thing to consider beyond HP, torque and weight numbers is the rear end ratio. If a newer engine is used that is comfortable revving higher along with an AOD trans, the rear can be changed. A 4.11:1 behind an AOD may go down the road at about the same rpm as the 390 and original automatic.

A 4.11 would certainly be helpful at stoplights too! :eek:

09-03-2014, 05:40 PM
His Cobra engine is all aluminum. I can lift that bare block above my head. His heads are all aluminum and so is the rest.

Cobras from that era never came with automatic transmissions. If you really wanted an automatic the only option was a Mustang GT with a cast iron block and heads with two valves.

Why? Because the computer ran the whole car and Ford determined that the Electronic Engine Controller (EEC) was too slow to also handle the electronic automatic transmission in a race engine.

I know, this makes little sense because the same aluminum 4-valve engine went in Marks and none of them had stick shift transmissions.

Red Polling was Ford's CEO at the time, and his Mark self-destructed before 1,000 miles. Believe me, that engine came back to Romeo along with managers and engineers who personally watched as the engine was disassembled. Turned out someone left a wrist pin circlip out of one piston and the cylinder wall had two deep witness scores in the bore liner.

The remedy was to use 'vision' on every piston, verifying all rings and keepers were there before the piston went to Block Assembly. I can't tell you how embarrassing that was for Romeo Engine Plant.

Joe, a 4.11 would be perfect with an overdrive transmission. I used a 4.30 with my 351W/AOD Mustang. For daily (expressway) commute, that combination was perfect and so fast, it beat the pants off of factory Cobras. At least a few times a week, I would race them in front of the plant in Dearborn. - Dave

09-04-2014, 05:48 PM
Engine and transmission are now out of the Thunderbird. Now I've got a giant hole to stand in and start taking measurements. Being able to see the complete steering set up, I think I can make it work just by fabricating some motor mounts for the 4.6. Also changing to a front sump pan will make this a much easier speed bump in the long road to come of this project.

After a little digging, the 2000 Lincoln Continental used the 4.6 with a front sump pan. Looking into the measurements on that pan now. I may be able to keep from buying a $300 Moroso pan.

Tall gears have always been an item on the list for this car. But I might have to factor in a spare set of tires in the budget ;)

Joe Johnston
09-04-2014, 06:59 PM
[QUOTE=Tall gears have always been an item on the list for this car. But I might have to factor in a spare set of tires in the budget ;)[/QUOTE]

and the list goes on!:D

09-04-2014, 10:49 PM
I'm liking where this is going. I want to put one of those 4.6's in my 40 merc.

09-05-2014, 01:51 AM
If you do Keith, get a sacrificial car from which you can take the electronics, cables, connectors, etc.

Now, there are a lot of old Romeo engines. I was never a big fan of the aluminum block but I do like the four-valve heads. Both blocks are identical in many ways so you can put four valve heads on a cast iron 4.6L block. Those heads come in LH and RH but the 2-valve aluminum heads are interchangeable. Both cranks are the same dimensions but Cobra wears a steel crank. Is there a difference in cranks? Not really because the stroke is so short.

This engine is under 300 cubes but when you put massive heads and timing chains on, it looks huge. With overhead cams, there are no pushrods. The 'lifters' are now called 'lash adjusters' because the plunger is the only part that moves, and rocker arms are now called, 'roller followers'. Roller followers have needle bearings that roll on the cam. That's why this engine needs no ZDDP in the oil.

Aside from 4-bolt mains, the crowning glory of the Romeo engine is the connecting rods. They are made of sintered and compacted powdered metal, scored at the cap, then pulled apart (not machined). When that hydraulic machine pulls the cap, it comes off with a very loud, "CRACK!" The mating surfaces are jagged which means each cap only goes together with it's perfectly mating counterpart. Caps cannot mate backwards or with other rods. Once mated and bolted, caps cannot move in any direction. The parting line is so perfect, it's very hard to find.

The pistons have full floating wrist pins (like FE engines), hypereutectic alloy pistons, moly rings, stainless valves and seats, Viton seals, a knock sensor and every modern feature you should expect in a top shelf engine.

With forged pistons, this engine can be super or turbo charged (but so can your FE engine). - Dave

09-05-2014, 10:36 AM
...I want to put one of those 4.6's in my 40 merc.One of our local hot rodders had one in his hot rod. From his firewall, the hood quickly tapered to the radiator, giving it a "V" shape. The 4-valve engine heads stuck half way out each side, giving the appearance that the engine is huge. Each valve cover was branded, "LINCOLN". It was VERY cool... His front end was king pin with spoke wheels and small disk brakes and lots of chrome. I believe his trans was a 6-speed Tremec. I wish I had taken a picture. - Dave

09-05-2014, 06:48 PM
Looks like itīs going to be a great project! I just hope you donīt put on too "big wheels". That will kill it.

09-12-2014, 06:13 PM
You got the Cobra motor but did you get the T-Shirt?

10-03-2014, 09:41 PM
Sorry for the lack of posting. I've been in and out of town, and in and out of the country for work. Not much progress has been made since my last post. Currently looking for automatic transmission options for my set up.