EXCLUSIVE: 1973 Pontiac Firebird

Josh MortensenBy Josh Mortensen

When it comes to buying a classic car online, you can’t ever have too many photos or too much information! Reader Rob E has decided to part ways with his ’73 Firebird, which he has been working on the for past 20 years or so. Being the kind of meticulous classic owner that he is, he wanted to provide as much information and as many photos of his Pontiac as possible! I want to thank him for that, it’s an interesting read and leaves you knowing exactly what your buying. He’s asking $17,000, but he didn’t mention whether that’s in US dollars or Canadian, so be sure to ask. If you’d love to give his Firebird a new home, be sure to message him via the form below!

From Rob – I bought the Firebird about 20 years ago, it was in pretty bad shape. It was a car that had been drag raced, by amateurs, so it never had any winter driving on it. Someone blew up the original Pontiac 350 and installed a Chevy engine, I think it had a series of engines. 350, 396, 454 sort of thing. Read between the lines, not winter driven. Interestingly, the Chevy engines right bolt in, no frame modifications were needed. This is the same frame as a Camaro, so not that surprising. Headers for a Camaro fit no problem.

They left it as an automatic, but installed a roll cage, a 6 point cage, to tie in the rear frame and the firewall. It also has welded in sub-frame connectors. So, the car chassis is stiff, it has original floors and frame rails.

Eventually they sold it to a kid, who had no skills, and the junkyard motor they installed was a wreck. He couldn’t fix it, so I bought it. Every fluid in it leaked, transmission, engine oil, rear axle all leaked. He drove it from Toronto to my place in Cambridge, and brought along motor oil, antifreeze and tranny fluid just in case!

Someone tried to steal the car once, the ignition column was smashed up, so I replaced it with a factory tilt column. That tilt column is nice with the roll bar in there. I have worked on the car every winter for years, so I never drove it in winter either. It has lived in a heated garage ever since I got it.

It has new rear quarter panels, repaired rear wheel wells, there was some slight rust in the wheel wells. The car came with a new passenger front fender and drivers door. I installed a passenger door bottom panel and patch on the drivers front fender. The rocker panels, floors, frame needed nothing.

It has a factory Formula hood, and I ordered a fiberglass front nose cone, which is at least 30 lbs lighter than the original nose ( which I have ). The vendor made a mess out of the nosecone, so I fixed it. I installed a used rear trunk lid, and removed the factory rear spoiler ( which I have ). The trunk lid eventually bubbled, so I installed a new aftermarket trunk lid, I think it was a OER part? One of those GM approved replacement trunk lids, a few years ago. The trunk lid and fiberglass nose were done last spring, 2 years ago.

The engine is a Chevy 400 small block, it weighs almost 200 lbs less than a big block Chevy, but is 50 cu in bigger than a 350. Also, it weighs less than the Pontiac 350. I am a machinery designer by profession, so, a goal was to cut weight. The engine has the 400 crank but 350 rods, good to 7000 rpm, with Keith Black hypereutectic pistons, which are lightweight to reduce inertia loads and allow better revving. Piston rings are individually file fit. It is bored to 406 cu inches. With the crank rod assembly it is technically now a “stroked” motor, so it has the torque that 400’s are known for but revs like a 350, or a 383. It’s a 383 on steroids. Rods were magnafluxed, shotpeened and straightened. The rotating assembly was balanced for 7000 rpm use. The shop that did that work builds engines for local stock car racers, and that’s all they do for 7-8000 runs.

I used the top quality parts for piston rings, bearings, etc and also installed a high volume oil pump. Distributor is HEI, with a separate lead coming from the alternator to the HEI module to get maximum voltage into the ignition. The control relay is run from the stock ignition switch wire that normally runs to the HEI module.

Heads are Vortec, cast iron, GM, with port and polish, valve job, gasket matched. Vortec are the best flowing heads GM made in the 90’s, better than double hump 202 heads, per a book I bought. Aluminum intake, dual plane intake, Quadrajet carb with some modifications, headers, retuned timing curve. The cam was selected for the kind of driving I do, which is street rpms. I like torque, and revving over 5000 rpm is not normal, so the cam is good from 1500 rpm to 5500 rpm. Street driving. More about performance later.

I didn’t like the location of the alternator, so I designed and mocked up a new set of brackets to locate it many inches lower and out of sight in the engine bay. Those brackets use existing mounting bolt locations. I made 10 sets of brackets and sold some to local speed shops, with instructions and hardware. I also moved the battery to the trunk, and you can shut it off with a simple switch to prevent theft. This also improves the weight distribution.

Brakes have a manually adjustable proportioning valve, because I installed rear disk brakes from a 79/80 Turbo Trans Am. If you decide you want to try some parking lot slaloms, which I did a few times in Toronto, you increase the rear brake pressure. At low speeds you can get away with this. It feels like someone threw out an anchor at 40-50 mph. At highway speeds, you could end up in the ditch if you leave the valve at that setting, as the rear wheels can lock up. So, once done having fun at the slaloms, you turn the valve out a few turns and back to normal, no tools needed.

The parts to convert the car from automatic to standard were sourced from a Fbody collector who had all the factory bits I needed, such as the bellhousing, pedal assembly, linkages. A custom drive shaft was made. Rear axle has a factory posi, which I rebuilt. The 3:42 gears were a factory option on some Camaros. New oil seals were installed at the time it was swapped.

Transmission is out of a Trans Am, so all the parts are factory, a Borg Warner T10. Not ALL the parts are factory. The clutch is a dual disk light weight, semi racing clutch ( McLeod?). The flywheel is solid steel (billet) SFI unit approved to 10,000 rpm, a 30 lb flywheel, I don’t trust aftermarket made offshore, if it can explode and take out my legs. Shifter is Hurst, either a Super Comp or a Competition Plus, whichever is better. I cut the shift lever shorter until it is just the right height, and it looks perfect. I removed the console, I like to look of the open floor, and think the factory console is average looking.

Suspension is mostly Global West. Front coil springs are called street/track, the car is lowered 1.5″ as a result. Shocks are Herb Adams adjustable, likely non adjustable at this point, they are over 10 years old ( maybe 10,000 miles old ). Sway bars are also Global West; they are 1 3/8” front and 1” rear. Rear Leaf springs are modified by moving the top leaf to the bottom, which lowered the rear by 3/8″, and changed the way the springs work slightly. It tracks straight off the line, and hooks up to point that rubber is actually hard to get unless you really abuse the car.

Tires are the best I could buy, Toyo Prox T1S. I spent $1600 on 4 tires about 8-10 years ago, and the rears still have lots of tread. The rims are off a 86 Trans Am GTA, they are used in IROC series of races, and are the lightest aluminum rims GM made (even Camaro ran Pontiac rims in the IROC series I heard ). I had to change the wheel studs to metric to use these rims, easy to change back to standard if you want to. A new front rotor will actually have the original Imperial studs, which are just knocked out with a hammer and pulled in place with washers and a lug nut. Same splines are used on the studs, so not a problem. Exhaust is dual stainless, headers are not stainless, but were replaced 3 years ago.

Interior is black, factory, it was an AC car but the previous owners removed all that stuff. Heater works and fan for defrosting the windshield if you visit a friend and the dew shows up. Drivers seat was recovered with matching factory skin, passenger seat and rear seats are original! New carpet, new headliner, new windshield, new door sill plates, dash pad is perfect, dash is not messed up, Sony radio installed in the unmolested dash, no factory radio. I have driven it every year since I bought it. It is reliable, looks great, corners amazing for a muscle car.

Story time – At a slalom event, I had the 2nd oldest car. I had the most highly modified car there as well. I was faster than Mazda Miata’s and other small import cars, and I was put into the C5 Corvette class as there was no class to fit my car. I was faster than 3 of the 5 Corvettes at the event. This was before I did the engine and the tires, and it was the 2nd time I ever did a slalom. I used to rally so have some idea how to drive.

A local guy grew up with his dad’s car sales business, mainly Porsche and Volvo. I took him out for test drive, he had a NSX at the time. I scared him on the ramps, and when I nailed it on the straight away he was blown away. His comment was my car pulls at 2000 rpm like an M3 or M5 at 5500 rpm. I can do 60 mph in second gear, 90 mph in 3rd gear, and have had it over 120 mph. Lose your licence time in seconds in a straight line. These speeds are basically around 5000 rpm, and I know I can run the motor higher, because I have.

I built the car to prove that you can make a muscle car handle, and you can. Pro Touring is all about it. I was doing this car before magazines wrote articles about Pro Touring. Now companies are selling new front clips, which will have better geometry, but, I really just wanted a fun driver. Knock yourself out if you want better suspension, lots of ways to improve it.

The average driver will not ever take this car to its full potential, but if it has only 400 hp and 3200 lbs, you have a power to weight ratio of 8 lbs/hp. I believe it is more like 450 hp, the engine build I based it on was 350 hp from a 350 motor, I have 406 cubes, and more extensive upgrades and a bigger cam. If it has 450 hp, that is 7.1 lbs/hp. Somewhere inbetween 7.1 and 8 lbs / hp is a safe bet.

If someone wants to take it to the next level, it is not cut up, blinged up, or messed up. Everything I did can be restored to original if you wanted to. There is a hole in the shift tunnel for the manual shifter, but some tin and a welder would correct that.

I have a lot of parts that came with the car, including the original Endura nose cone, rear spoilers, console, assorted parts, rims and trim rings. I am not sure if it was a base Firebird of Deluxe, it had chrome trim on the rocker panels and on the wheel wells, which are long gone. So, there is the story. Questions?

I want to thank Rob again for the detailed write up and all the great photos! These are great cars, clearly he has enjoyed this one, and values are on the rise. I know this one isn’t all original, but all the upgrades should make that much more fun to drive! If you have a classic that needs a new home, please consider listing it with us. And if you can send us this many great photos and and information, that would be awesome!

Asking Price: $17,000
Location: North Bay, Ontario, Canada
Title Status: Clean
Mileage: 20,000

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  1. Jim B

    Neat car and great story! I hope it finds a new home quickly!

  2. JW

    Great write up to a very nice car.

  3. Coventrycat

    One of the best styling years for Firebirds and Camaros. Nice car, and tastefully done.

  4. Sunbeamdon

    Great car; great write up (done right)!

    I’ve been through North Bay in 1962 on the second Shell 4000, navigating a Pontiac Acadian – my driver bailed out in Winnipeg – something about his wife going into premature labour. Great story on-line. We followed the second and third Acadians which had lost its fuel tank in the mud in northern Ontario. I had to reattach the carriage bolts which slid out from the gas tanks or we, too, would have lost our tank.

    • Bobsmyuncle

      Tough to find ANY info on the race let alone hear from someone IN it! I read some time ago that some effort to revisit the rally was in the works. I have some long term plans to do up a Lark as it may have been presented in the rally, won three years in a row if I’m not mistaken.

  5. KevinW

    Dang, I wish I could afford this beauty!

  6. Fred W.

    That very first picture really grabs you.

  7. rs

    Just a very minor point, it’s good to see dual exhausts that look like the factory did them and not just a pair of long straight pipes hanging under the car like trombones.

    • Kent Pearson

      The factory did not provide dual exhausts, There was a single stack from the where rhe ends of the manifolds joined back to a single lateral resonator with two short exhausts extending of that. I ripped out the single on my ’75 along with the cat. and rn new pipes and mellotones all the way back from each manifold and out.

  8. Mark Lawson

    This may be the best ad I’ve ever seen by a private seller. If I had the cash on hand, I would already be on my way to Canada. Bravo!

  9. Doug Towsley

    WOW! Double thumbs up from me, Not only the kind of guy I would want to buy from, but the poster child of how to properly sell a vehicle.
    I had a few Camaros but not my favorite cars. But I always like the styling of these better. I also love all the mods this seller did. Sensible and well thought out, Not just throwing money at a car but good value for return. I even like those gold honey comb rims and while I am not sure what I will use mine on, I have a set I bought cheap at a swap meet. Clearly this guy did his research and this is an extremely good value buy. If I was smart I would sell of several of my projects and buy this.
    About the only things I would change (minor details) Is I Liked the rear spoilers on these,, I would ceramic coat the headers (Does wonders, ID & OD) I would swap out that clutch fan for a thermostat controlled perf electric fan, and I would get rid of the Quadro-junk and run a Holley vac sec modified 4 barrell. (I can make those run well, good perf and fuel economy at same time).
    Again, Best ad I have seen in years. Sweet ride!

  10. Jeffro

    Uh yeah…what everyone else said!

  11. William Piwowarczyk

    I guess I see something different. Definitely not worth 17. Front spoiler is tipped way down, back bumper is crooked and things like that can be minor but makes me wonder if little things like that aren’t fixed, then what else? Yes I like the car, just not for 17. 10 maybe 12 grand very most.


      The guy spends so much time, money and effort to build a great car and then fits the front spoiler to resemble a snow plow?

  12. Doug Towsley

    Minor issues, they guy also makes it clear he has the other parts including original nose, So he is not a body and paint specialist,, so what? Why bust his chops? Heck, a lot of people I know drive hot rods around that look like hell but run like a scalded cat, some of my own projects over the years were a “Work in progress” for years. Seems like nit picking. I do know what kind of time and labor is involved and see if you can build anything on this level for that kind of money. If you do everything yourself,, sure I could come in well under 10K plus I have tons of parts rat holed. But to buy all this stuff and pay someone to do the work you would 3x the asking price. Thats the point here. DIY vs Checkbook builds. My $0.02

  13. Stu

    I honestly don’t see anything special here. The photos would suggest that the owner is not nearly as meticulous as the write-up would suggest. Lucky to get $8 CAD.

    • Scot Douglas

      I respectfully disagree. Hard to find examples half as good in Michigan for similar prices – if he is asking CAD. 🙂

  14. Rob

    Hi Guys,

    I appreciate the positive and negative comments, and the negatives are interesting.

    Yes, it is not a perfect car, and to maintain it as a perfect car would require a great deal of effort.

    Part of the reason its for sale is I am not willing to put the effort into it, and after 20 years I’ve had my fun.

    The front air dam and rear bumper show worse in pics than I have ever noticed in the real world. Pics are a great way to see details. I was suprised when I took them, but, I posted them anyways. What you see is what you get.

    If you want a show car, it won’t be listed at this price. Lots of Trans Ams and Formulas on the web for $40k and up, that won’t corner or accelerate with this car. There was/is a $150k plus Trans Am listed in Toronto.

    I’ve driven some, particularly a 73 Trans Am 455 SD. That car had 4 wheel steer. Point into a corner, mash the gas, drift the back end out and power slide it. That is not what this car does.

    The next owner can either fix those issues and have some “I did that” fun or send it out.

    • Bobsmyuncle

      While it’s clear where the money and effort went, and while I and many others appreciate that, you can’t compare your car to a factory OEM car in value.

      If you were still in Cambridge I’d be there in 15 minutes to look closers.

      Cool car, great description!

    • Jeffro

      Side note: I installed those same tires on my truck, and it was night and day. Those tires rode very well and stuck to the road. They were pricey, but we’ll worth the $.

      • Rob

        Those tires are amazing.

        Made a huge difference in handling and ride. Cost me $1600 for the tires, and I scored the rims at a swap meet in Waterdown.

  15. Rob

    Oh , forgot to mention is is $17k Canadian.

  16. Don H

    Cool car Rob ,thanks for not making it a boring Tans Am 👍

    • Rob

      Well, I like the Trans Am look, but, honestly, I didn’t want to turn it into one when the serial number wouldn’t back it up.

      I removed the rear spoiler, and had my family come out, we all agreed it looked better without. Some days I wish I had it, other days I like the look of the rear without it.

  17. RoughDiamond

    Oh yeah, Rob! Sweet build and I really like how you “personalized” the car to your liking. The next owner can do likewise. Try building that beast for anything close to 17K Canadian or more like 12K American I believe.

    • Rob

      Totally agree.

      At this price it is good value.

      I think its fair, but, there are lots of people who want to “score” a deal.

      It’s not costing more than insurance and plates to keep it, no rush to sell it.

      Insurance has it valued at $20k Canadian.

  18. Joe M

    Well done, nice engine choice. Small Block 400 puts out some impressive horses when done right. Wouldn’t mind taking this one out for a run. Garage is full right now… I pick a lot of savable Camaros and Firebirds out of the auctions… Nice car, I like the thought that went into this one…

    • Rob

      Thanks, I like the end result too.

      I had lots of time to think it through.

      I considered a 4 link rear suspension, and a Tremec 5 or 6 speed. I used to work at a hot rod shop, and we did a Corvette with a 6 speed. The owner loved it, but, was constantly shifting it. 4 speeds is fine for street, 5 and 6 speed are for the track where you want the engine in the sweet spot for exiting a corner.

  19. Big Ed

    Hey Rob, I would have the engine bulder to tap the block and water pump on both sides to plumb water to the middle of the block to reduce head gasket temps in the area of the siamesed exh valves (old NASCAR trick). Run twin oil coolers for engine oil and trans fluid, when hwy cruisng it.

  20. Big Ed

    Just wanted to add that I was all smiles in that you built my car except in the wrong body. Hope you get your price!

    • Rob

      Sharp looking car, and some motor in there!
      Mind if I ask why the lines coming out of the valve covers? To collect oil vapor and keep the engine bay clean? Or to a vacuum pump? I have never seen that before.
      I like your body style, and you obviously put more effort in appearance than I have!

      • Big Ed

        Just oil vapor lines routed to that single canister. Engine was 13.5 to 1 with 58cc combustion clambered AFR 215 hds. Has Comp Cams 258/254 HR street cam and rated at 580hp. I use copper head gaskets with copper spray sealant.

      • Rob

        I like the overall appearance, shiny and tech looking.

        Nicely done!

        Thanks for explaining, and the trick about cooling too.

  21. Jubjub

    Hope it’s as fun as it sounds! Nice to see one set up for more than going in a straight line. Cool ride.

    • Rob

      My first real fun car was a 74 Ford Capri, V6 2.8L, 4 speed.
      I did a lot of engine work on it, and suspension, tires, rims.
      180 hp in a 2300 lb car. Rally grind cam, usable power from 1500 rmp to 5500 rpm. I smoked a lot cars in a straight line, and then waved good by in the corners.
      Back in the 70’s there wasn’t much to keep up, except the older muscle cars, and they didn’t handle.
      My brother would trade me his 76 Corvette because mine was more fun to drive.

  22. Tirefriar

    This is roughly $12500 in real currency. all the $$ and effort that went into building this car alone is probably close to the selling price. If the car has had the rust repaired professionally and is rust free as claimed then this is a good deal. A clapped out Firechicken of similar vintage, especially with a stick,will run well over the north side of $5k. And most of the heavy lifting has already been done here. Hop in, shut up, hang on and enjoy!

    • Rob

      Totally agree with you.
      Not sure you could rebuild it for the parts cost alone.
      Not that I can prove the rust is not an issue, but, the paint is atleast 10 years old, there is 1 bubble so far on a rocker.

  23. Doug Towsley

    My Currency is Beer slips, whats the exchange rate on that??? (I am agreeing w/ you Tirefriar)

  24. Rolf Poncho 455

    Great performer yes it needs some T L C and sorry for this a Pontiac motor
    but the chevy makes lots of power and is cheep to build I will take it anny day

    • Tirefriar

      Actually my only gripe with this car would have been the Chevy lump had it not been for the seller’s reasoning and the build. Poncho motors are stump pullin’ torque monsters. I personally would have sourced and built a 400 Pontiac engine. I’ve done that for my ’68 Firechicken and it didn’t need a whole lot of tuning to get it to 400 HP at the flywheel. Just bored it 0.060 over, hotter cam, midrise manifold with a reworked Q-jet. But the seller took a whole different approach and that’s cool. I didn’t build it to auto cross either. Just to fry those fox body 5.0 mustangs that thought they were the sh!t.

      • Rob

        There are days I wish I had a Poncho motor in there. I love torque.

        I like less weight better, and the 400 block basically fell into my hands.

        Like you said, I had hopes of autocrossing it, but no one up my way does that. I would have to drive the car 4-5 hours one way to run it. I used to in S Ontario, 1 hour from Toronto, so I ran it a few times there.

    • Rob

      That is a great pic. Amazing styling on these cars.

      Your front air dam / valence fits great.

      Like the blacked out grill, bezel, and darkened turn signal.

  25. the one

    Bunch of hosers. Take off!

  26. Sunbeamdon

    Hi Bobs My Uncle – do a web search for Shell 4000 and you’ll get lot’s of back story – this is the link “shell-4000-rally.org”

    I’d forgotten that the Larks were first and second in 1961 and first in 1962; my brother-in-law, Ken Dunsire, (Hillman), ran in 1961, I ran in 1962, my rally partner in BC, Art Bayne, ran in 1963 (Corvette) – lost many points because he stepped-in to drive the hill-climb in Kelowna without the driver in the passenger seat, even though he scored best time.

  27. Doug Towsley

    That Rally info is great, First I ever heard about it… thanks for posting about it.

  28. Joe Defelice

    This would be a really good time for me to match up the powerball numbers!! :p I can appreciate all that went into this car!!!!!

    • Rob

      Thanks, it was fun and I learned a lot doing it.

      Scared many a passenger with it, not intentionally of course. Grin…

  29. Ron E Bee

    fantastic. Super Cool Car. I wish I was in the market, one of my favorite body styles, love the formula hood. I’d probably put the rear spoiler back on almost immeadiately

    • Rob

      I love the styling too.

      Interesting to see how many advertisements have one of these in them. I think they are hitting their stride, the early Mustang / Camaro first gen bodies are great, but, they have been done and done and done..

  30. Cattoo

    I absolutely love this style of bird with the formula hoods. Like the way the intakes are right up in front. Had I the other 11,500 dollars needed I’d be all sorts of happy and Rob would have ca$h money neatly stacked in an envelope in his pocket. Oughta take a loan out against the house or something. Love the ride Rob. Very nice.

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