Building a ’57 Bel Air 2-Door Convertible From a Cheap 4-Door Hardtop

1957 Chevy 4-Door Hard Top To 2-Door Convertible Conversion
Complete 1957 Chevy 4-Door Hard Top To 2-Door Convertible Build

Dan is hot on the next DD Speed Shop project: a 1957 Chevy Bel Air (soon to be) convertible. He’s wanted a tri 5 convertible for a long time but has been totally priced out of the market. So naturally, he bought a cheap 4 door hardtop that he’ll first convert into a 2 door then cut the top off of it!

The following videos and snippets document the complete build of the 1957 4-Door Hard Top To 2-Door Convertible, which is also summarized below.

Bringing Home The Cheapest 1957 Chevy Bel Air (Soon To Be) Convertible

Converting a 4 Door Hard Top Into 2 Door Convertible

Door Delete, I Have A Plan…

So, when you’re building a 2 door convertible out of a 4 door hardtop, there are a few things that gotta go. The roof and extra set of doors have served their purpose over the years but it’s time for them to move on.

Dan decided to start by transforming the 4 door hardtop into a 2 door hardtop.

Granted, the roofline on a 4 door is different than a 2 door, but you get the point. Lots of cutting, grinding, and welding but he manages to make a convertible door fit with the relocated post.

With the post moved, the rear door was skinned and used as a quarter panel filler…

A Little Off The Top…

The convertible doors have been attached and extra bracing welded inside the car. Dan’s hoping the car won’t just fold in half the second the roof is cut off. But more importantly, he hopes this convertible conversion actually looks like a convertible! There’s a big difference between a car with no roof and a convertible.

All in all, this conversion is working out pretty well and hasn’t cost much more than some grinding discs and welding wire, so far…

Factory Rag Top At Home Chassis Swap

The convertible needs more strength so it won’t fold in half. Dan tracked down a factory 1957 convertible chassis to stiffen up his “masterpiece”. He had to pay up a little for the proper chassis but with all the added stiffening and supports, it was worth the cost. Also, he hopes a proper chassis will help with resale down the road (if he ever decides to sell anything).

Doing a frame/chassis swap in your home garage with NO hoist can be a bit of a challenge. Dan figured that as long as he was never under the car while it was “supported” he’d be “safe”. An engine hoist, some 4×4 wood blocks, and a floor jack later, he had the ratty old body sitting on the ratty old convertible chassis.

This was a big job to do at home, but not impossible. Watch…

Factory (Reproduction) Rag Top Sheet Metal Install

With the roof cut off the “1957 Chevy Bel Air Convertible”, Dan installs reproduction rag top sheet metal around the giant roof opening he’s created, as Tri-5 convertibles have unique panels on the top of the quarter panels and rear package tray to accommodate the canvas top.

These panels were pricey for sure, but once installed, the car will have a factory convertible appearance…

Cutting a 1957 Chevy Belair Convertible Half In Two! – It Was Bad, Real Bad…

This is your classic “Best laid plans” situation. Dan’s been putting floors pans in Tri-Five Chevy’s from the bottom for years. Well, this 57 Chevy had no roof, so the floor pan could easily drop in from the top right? WRONG! This floor wasn’t fitting no matter what he did.

Well, Dan lost his patience and started cutting till it fit. So he cut the car in half, then the whole car folded in the center, and nothing fit. With a little flexing, cursing, prying, and ingenuity, we had her straightened right out!

No one ever said turning a 4 door hardtop into a 2 door convertible would be easy, but he’s making progress every day on this hillbilly convertible.

Engine Or Motor? 1957 Chevy 4 Door To 2 Door Convertible Conversion Gets A New MILL

The metalwork on the 1957 Chevy Belair 4 door to 2 door convertible conversion has all been fit together. The next step is to get the car on all 4 wheels and weighted down with a driveline. Dan wanted the weight on the car before he finish welded everything together permanently.

The factory convertible frame sure stiffens everything up. Nothing changed with the weight in the chassis. That being said, fitting the transmission in the X frame was no easy task. This motor/trans install fought me much more than it should have. It’s in, and ready for the next step of the build…

Butt Welded Repair Panels

Time for a little more panel replacement on the ’57 Chevy convertible project. Up until this point, we have taken a 1957 Chevy Belair 4 door hardtop and transformed it into a 2 door convertible. Doing this on the cheap meant re-using most of the 4 door sheet metal and only purchasing the essentials.

The car was in a classic car junkyard for 20 years being parted out. Unfortunately, some of the “parts” pulled off were quarter panel patch sections for another car. Fixing dents and rust is one thing, but not having a panel to start with is another challenge.

Luckily Tri 5 Chevy replacement body panels are readily available and make for a factory repair. This convertible conversion is turning out nice enough that I think it warrants the added expense.

In this instructional segment, Dan shows how to replace quarter panels on your hot rod project. This was done in two sections but the same principles apply to full panel replacement…

Nice Rear End!

Spare parts! The key to any successful budget build is spare parts! Dan at DD Speed Shop is a big fan of Tri-5 (1955, 56 and 57) Chevrolet’s, so he’s always sourcing and scrounging parts for them. He’s a believer in sticking to a brand and style of cars so the build becomes much cheaper!

He recently sold a 1956 Chevy, but the buyer didn’t want all the parts on the car. He saved the entire front end, fuel system, exhaust, steering, etc. Well, all that stuff is interchangeable with this fine ’57 Chevy ragtop project. So we swapped parts and kept the budget low.

The real win on this 4 door to 2 door conversion was a new set of leaf springs for only $100! Such a score, especially in a time where lots of parts (including tri 5 leaf springs) are on backorder!

Non Stop Welding!

In the previous episodes, Dan has taken a rotted-out, left-for-dead 1957 Chevy Bel Air 4 door hardtop and converted it into a 2 door convertible. Up to this point, everything has just been “tacked” into place. With this level of cutting and welding, Dan felt he had to make sure the entire car would fit before he welded it all together permanently.

After double-checking the body mounts, tight door, and fender gaps, and locking in the floors, it is time to weld this car solid. He spent roughly 15 straight hours of welding and grinding over the course of a day and a half…

Inner Structure

Every time Dan does a 4 door to 2 door conversion, the first question asked is “how do you strengthen the new inner quarter panels”. It’s actually quite simple — section the old inner door structure and weld it in.

That process has worked for the last few 2 door sedans Dan has built, so he has used the same procedure for the convertible conversion. Measure twice, cut 3 or 4 times, and the panel fits perfectly!

It’s all welded, seam-sealed, and painted. Dan tosses in some carpet and a seat — before you know it I’ll be cruising in style!

$100 Amazon Wiring Harness, Will It Crank?

Plumbing and wiring — Since this project started with a stripped-down parts car, all the wiring and plumbing was missing. Dan sprung for the cheapest wiring harness Amazon offered! He tells us that it honestly wasn’t that bad and says he’d buy another one.

The “X” frame built specifically for Tri-5 rag tops proved to be a challenge when plumbing the brake and fuel lines. He says “Don’t even get me started on the exhaust fitment!”

Who would have thought transforming a 1957 Chevy 4 door parts car into a slick 2 door convertible would be so much work?!?

Parts Car To Cruiser – 1957 Chevy Belair Convertible First Start In 20 Plus Years!

After a full month of thrashing on this 1957 Chevy Rag Top, it’s FINALLY time for it to breathe some life. Bear in mind, Dan bought this car for $1000 out of a wrecking yard at the end of July as a 4 door hardtop parts car…

Granted, the motor and trans didn’t come with the car or have been sitting for 30 years, but having a left for dead project car start for the first time is ALWAYS a good time.

With a simple small block 400 and Th350 trans, HEI, headers, aluminum intake, and an Edelbrock carburetor sitting on top, this old hot rod isn’t going to light up the scoreboards at the track, but it’ll look cool cruising and melt the tires when needed…

Life Is All About Timing — Static Timing a Small/Big Block Chevy

Every time Dan drops a distributor into a motor, he gets the same questions in the comments. How do you know where to drop it in? How do you set the initial timing? How do you find top dead center?

Ignition timing is very simple but very important to make the car run properly. Dan says:

I always “static” time my motors when I’ve had the distributor out. Static timing is a function of essentially setting the timing by hand with the motor not running. Then it can be fine tuned with the timing light after.

This video contains information about timing any small/big block Chevy.
283, 305, 327, 350, 400, 396, 427, 454 ect. This may not be a perfect tutorial, but it has always worked for me.

Dan at DD Speed Shop

Certified RIPPER – 1957 Chevy Rag Top Smoke Extractor – GARAGE BURNOUTS!

You know the rule: First miles are BURNOUT MILES!

Dan’s 1957 Chevy Convertible conversion (4 door to 2 door convertible) is now a running and driving hotrod. The little 400 was running in the last video pretty poorly. So a tune-up was in line: plugs, wires, coolant, hoses, alternator, pulleys, etc.

Once the motor was running better, Dan moved on to replacing the front sheet metal. He found a cheap set of driver-quality fenders so he snatched them up and bolted them into place.

If you’re keeping track, Dan has already replaced: front fenders, hood trim and rockets, floors, doors, rockers, lower quarter skins, and the deck lid. That’s a lot of “new” sheet metal on an old car.

She’s rust-free and ready for bodywork and paint!

Bondo 101 ~ Bodywork and Primer Prep

Dan is at the point of the build that he hates the most — Dreaded bodywork!

In this video, he strips all the trim off of the car and grinds all the welds down flush and applies filler, then brought down with varying sandpaper grits from 40 to 320. He’s not going for perfection here but trying to flatten it out enough for a coat of primer. Having the rear doors filled and primed will really bring this car together. A few days of sanding then he’ll lay down some red oxide and bolt on some trim…

Cheap Primer and Full Assembly of the ’57 Chevy Convertible Conversion

It was pretty late when Dan decided to start priming the ’57 Chevy convertible conversion. Since turning the 4 door into a 2 door, he really wanted the back doors filled and primed. That always changes the look big time! So he painted ’till about 1 am and then called it a night.

Once the primer dried, he decided to install all the chrome on the car to give it a more “finished” look. Cutting and fitting all the 4 door chrome onto a 2 door convertible trim turned out to be a bigger job than he expected.

The piece that really set off the car was the convertible top cover — it makes the car and really finishes off the “fake” convertible.

The 1957 Chevy Convertible Gets Chrome-In-A-Can and Glass Packs!

Dan reworks the roof area above the windshield for the proper “convertible” look. A proper convertible windshield frame is about $700 plus adding all the chrome/stainless. So clearly, a little welding and chrome in a can are much more budget-friendly.

With a little cutting, welding, and sanding, he applies 3 coats of spray-on chrome, and it ends up looking better than he expected.

With the car looking cool, it was time to make it sound cool. Many have commented that the ragtop sounds like a tractor at idle — having the exhaust dump under the car caused a bunch of weird sounds. Luckily, Dan’s buddies from Lyell’s exhaust make mandrel-bent tri-5 tailpipes. So I ordered a couple of sets and install them on the car, and what a difference it makes having the exhaust dump out behind the car. Another win and another step closer to driving this hot rod down the road…

FIRST DRIVE! Wrecking Yard To Cruising In 6 Weeks!

It’s been about 6 weeks since Dan dragged this car out of a classic wrecking yard. What started out as a rotten 4 door hardtop is hitting the road for the first time in years as a 2 door convertible.

Dan has just a few last items to finish up before he can hit the road — wiring and lights are a must. With all the lights working, his friend Mur came by to help him set a quick alignment.

Cruising around the block after thrashing for 6 weeks is such a sweet payoff. Dan says that he’s shocked how well the car drives considering how far apart this car once was…

In the previous video, Dan went for a teaser cruise around the block. Well in the days after that cruise he finished all the little things that needed to be taken care of: Lights, horn, and a quick carb cleaning and this old girl was ready for some miles!

I’m going to put my stamp of approval on this build. Everywhere we went got thumbs up and smiles all the way around. A proper paint job is in order for next year.

Dan, DD Speed Shop

$5,000 Build Cost Break Down

1957 Counterfeit Convertible 4 Door Hard Top To 2 Door Convertible

Complete Build Start To Finish

Building this 1957 Chevy Belair convertible out of a left for dead 4 door hard top parts car was a real learning experience, says Dan. She’s a little rough around the edges, but Dan says that he feels like a million bucks driving down the road.

Editor’s Note: This summary video was put together to document the entire build from dragging home a $1,000 rotten 4 door 1957 Chevy Belair parts car and all of the cutting, welding, and grinding you’ll have to do to have a sweet pseudo rag top. Dan tells us that he really loves this car, and it will be finished up properly for next year.