Crate Engine Swap: 1973 Triumph Stag

Owning a Triumph Stag usually means sitting on a knife’s edge, waiting for something expensive to go wrong with its unique V8 engine. That shouldn’t be an issue with this 1973 model, as it now sports a bulletproof American V8 under the hood. The vehicle has been sitting for many years, so it will need to be revived. However, that could potentially be a straightforward process. The Stag is located in Archer, Florida, and has been listed for sale here on eBay. The BIN for the Triumph is $16,000, although there is an option to make an offer.

The Carmine Red Triumph is a striking looking car, and the first piece of good news is that it appears to be completely rust-free. The lower body extremities and the floors look particularly clean and dry. That isn’t to say its perfect, because there are a few minor dings and dents in the panels. The paint is looking tired, and I think that a repaint will be on the cards in the near future. The Stag is also fitted with a factory luggage rack. It will be a matter of personal taste as to whether that stays or goes. One item that might require attention is the original alloy wheels. The black sections are beginning to look patchy and would benefit from some restoration work. Otherwise, the trim, chrome, and glass are all in good condition and should present well after a thorough clean.

What was hidden under the hood of the Stag typified everything that was right with Triumph, as well as everything that was wrong. The 2,997cc V8 was specifically developed for the Stag, and it showed so much promise. Unfortunately, it was never able to deliver on that promise. If you ever study automotive engineering, I doubt that you will ever encounter another engine so heavily riddled with design flaws as this one was. A general lack of quality control meant that engines were surfacing with casting sand in the cooling jackets…30-years after they had been built! Those water jackets were already marginal, so this simply exacerbated the pre-existing cooling problems. A poorly placed water pump added to the woes, meaning that overheating issues were the order of the day. Angled cylinder head bolts left the engine susceptible to head gasket failure and cylinder head warping. Timing chains were also a problem, and the fact that they were prone to stretching and subsequent failure meant that they needed to be replaced regularly. Otherwise, your little V8 could potentially produce some loud and expensive noises, followed by an eerie silence. All of these failings would have been forgivable if the Triumph V8 had been a jet. However, with only 146hp available, it wasn’t even close. Those problems are a thing of the past with this Stag, although the original engine is included in the sale if the next owner would like to experience a unique brand of misery. In its place, we now find a bulletproof Ford 302ci crate engine. This should not only be significantly more reliable but should produce noticeably more power. This conversion was undertaken in around 2009, but the Global Financial Crisis meant that it never made it onto the road. The owner assures us that all of the conversion work was performed professionally, which is reassuring in a case like this. The engine doesn’t currently run, but everything is hooked up ready to go. It should only be a case of going through the normal resuscitation process to fire the 302 back into life. Of course, the suspension, steering, and brakes will require a thorough check. However, this is all part-and-parcel of reviving a classic that has been sitting for the better part of three decades. It is probably worth noting that the 302 is heavier than the original V8. That means that once the Triumph is returned to the road, it might require some re-engineering when it comes to the question of front springs and shocks.

A neglected Stag can show its age with deteriorating interior trim and switches. Generally speaking, the interior of this vehicle looks to be quite promising. The glass on the gauges is slightly cloudy, and I’m not sure whether these would respond to cleaning. The switches for the power windows are also showing some deterioration, but I have seen these successfully restored by patient owners. There is some fading of the timber trim on the dash, and I would be making a concerted effort to restore this before I considered replacement. A set of replacement timber sells for over $1,000, which is enough to take your breath away. The driver’s seat has some outer edge wear, and the carpet is also faded. However, the reality is that if you wanted to use the car as a survivor, then the interior would be fine as it is. The Stag was designed to be a luxurious sports car. As a result, it comes with air conditioning, power windows, and an adjustable wheel. One interesting thing to note is the fact that the original radio is still present. More often than not, these have made way for an aftermarket stereo of some description.

The Stag represented Triumph’s attempt to challenge sports car offerings from Porsche and Mercedes-Benz, and on paper, it showed a lot of promise. Unfortunately, the design flaws in the engine were not only insurmountable, but they made their presence known from day one. This did damage to the Stag’s reputation from which it never recovered. Far from being the sales success that Triumph envisaged, a mere 25,877 cars were produced between 1970 and 1977. Only 2,871 made their way to the United States before sales ceased. That does make them a relatively rare car today, and with the engine upgrade that has been performed on this car, it has the potential to at least be reliable. Clean and original examples can easily sell for more than $25,000, while pristine cars can command $40,000 or more. This Stag is neither pristine nor is it original. To me, that makes the BIN price seem optimistic. If you are interested in this British classic, then I would be inclined to try my luck with a reasonable offer first. Who knows, but you might get lucky.

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  1. Howard A Member

    Um, sorry Adam, a major blooper here. Sure looks like a SBC to me. Maybe a GM 302? I’d think it is a proper swap. I always thought the Stag was a neat car, kind of a Spitfire on steroids, but as mentioned, the Stag motor was awful, and if offering a V8, should have gone with the Rover/GM 215 V8. Nice if it has a GM Turbo Hydramatic, otherwise, I think these used Borg-Warner automatics, still a sweet ride. Make most Corvettes nervous. Very cool find.

    • Lynn Member

      Not a chevy 302. All of those are restamped and in Camaros

  2. Steve Bush Member

    Looks to be in decent shape but at $16k is overpriced for a non running Stag. And Florida classic car dealer floats bs story about the previous owner and the “2009 financial crash.” Would think since the engine is apparently a basic SBC, he would fix it and then be able to get his price. Dealer Titus even gets the dates wrong. It’s was the 2007-08 crisis/crash.

    • Little_Cars Little_Cars Member

      Having lived through the last crash with a colleague, 2009 is the year we typically say things began snowballing financially. The origins go much further back of course, but 2009 was a REALLY bad year to start up a business. The only thing good to come out of dealing in cars that year was Cash for Clunkers which winnowed down a lot of crap cars from the driveways and yards of our customers.

  3. Maestro1 Member

    I am too far away for this but an enthusiast of the car, engine issues notwithstanding. The asking price is much too high. Adam is to be thanked for a good post. I drove one for about three-five days in normal commute traffic in rush hours in California, a period when normally all the bad stuff shows up; no problems. I gave it back to its owner, a San Francisco Assistant District Attorney, and what followed was a period of much time spent at her mechanics’. We both loved the car, it’s a great concept and mildly eccentric in design, so the engine switch is a great idea. I think either Adam or someone, maybe Howard, suggested a transmission change as well, and I would do that. Someone should buy this and invest
    in it. Never mind Market Values. Fix it and you won’t be disappointed.

  4. That Guy

    At this price it should be original and turnkey. It’s my understanding that fifty years later, the quality and engineering issues with the Triumph engine have been largely solved by specialists. These days, an engine swap may simplify maintenance but reduces the car’s value.

    This car would be a reasonable buy at a 65% discount.

    • Touringfordor

      Yes, most of the issues have been solved. High capacity radiator, vinton O rings, and modern head gaskets. Ironically, the angled head bolts and badly placed water pump were required by Saab, who cooperated on the engine design.
      I had one for several years, and loved it dearly. Sold it when the foam in all the seats crumbled. Looks like this one has the same issue.

  5. Ridge Runner

    Ummmm……am I missing something ??? That engine looks like an older small block Chevy with a points distributor

    • Steve R

      OE points distributors were often used in swaps due to clearance issues, kits to convert these to electronic are inexpensive and readily available.

      I’d bet the engine is not a 302, but a 305 instead. They are cheap and have been readily available for decades, unlike the 302 Chevy.

      Steve R

  6. Dusty Stalz

    The pics do a great job of hiding the big dent in the LF frender. The engine pic also does a great job of showing this is not a Ford 302.

  7. Doyler

    Say what you want about that Triumph V8 (And a lot can be said) but it sounds sublime.

  8. Jeff

    For sure the motor is a Small Block Chevy. The cylinder heads have accessory bolt holes so the engine is a 1969 or later. I believe the first year for a blue chevy motor was 1977. The reason why it does not have a HEI distributor is because it wouldn’t clear the firewall. The motor might be a 110hp 262 ci or a 305 ci 130hp. Both of them are duds in the horsepower department. The water pump appears to be the early short version and does not have the top bypass fitting.
    The seller should revise their ad and note it’s a preposterous mishmosh of unknown origin.

  9. ken tilly UK

    I’m surprised that not one of the comments so far has remarked that this car actually has a hard top. I have seen many of these cars over the years but don’t ever remember seeing one with a hard top. This one really suits the car.

    • Little_Cars Little_Cars Member

      I had an opportunity to locally buy a match to this car, red with hardtop even, just last month during an online estate sale. The final bid was $701 dollars. Came with the original engine set aside and a Nissan Z motor under the hood. Not running and a wiring nightmare. The only difference was it had wire wheels. Well bought at $701….I bid $700. Grrrrrrrrrrrrrrrrrrrrrrrrrr

  10. matt

    Ford engine would have distributor up front…looks like a chevy.

  11. GDTOKC

    Left rear quarter looks a little less than original. There is a crack line over the left front headlights. Is that just a deep scratch as it extends to the fender or is part of the Stag fiberglass and is it a crack?

  12. steve sammut Member

    That hardtop was an option and it was actually marked as a car with 3 tops, if you can consider convertible top down as a top. So, top down, convertible top up and this hardtop option…that comes off, by the way. I believe Triumph wanted to pursue the Mercedes 230SL market when they introduced this. The funny thing is, they had NO issues with their prototypes as those engines were build by hand, but when they “mass produced” them, the work from the foundries left much to be desired. As noted above, the water pump was an ill conceived idea, as were the head bolts. These cars were prone to overheating. The interesting thing about that is that the light that came on when the engine got hot had electronic gremlins…so much so Triumph finally told their dealers to disconnect the lamp. So, lets see….dubious water pump, no hot light….what could possibly go wrong.

    Also, Rover and Triumph were rivals until they came under the British Leyland domain, which could explain why Triumph didn’t use the Rover V-8. In truth, the 6 cylinder engine from the GT6 would have worked just fine, but again, Triumph was after the luxury market with this car.

    As for this car, $16k is a large number for a non runner. I think there is a little bit of BS with the sellers story. If that was a crate engine, you put it in, start it up and drive it. You don’t go through that cost to not fix what ails it. I’m thinking that engine isn’t new, has miles on it, they put it in thinking it would start and it never did….so they left it alone. Regardless, for 16K, you should be able to drive it.

  13. John

    Clearly a GM motor and no discussion at ALL of its transmission. Does it have one? Surely its not the OEM unit. Nice looking car, though.

  14. V8roller

    August 2019 – yes, you read that right – it was on eBay from the same dealer. Here it is being commented on BV8,65606

    At that time was said to have a 327 SBC. And was said to have been stored twenty years. Was offered in an auction, topped out at $4,500.

    Seems this dealer makes up his stories as he goes along.

  15. V8roller

    In August 2019 – yes you read that right – it was on eBay from the same dealer.
    Here it is being commented on BV8,65606

    Was said to have a 327 SBC.

    So either he forgot what’s in there or he makes it up as he goes along.

  16. V8roller

    This was on eBay in August 2019. Same dealer. At that time he said it had a 327 SBC.

  17. Jeff

    Doubtful, a 327 motor with accessory bolt holes in the cylinder heads was only available in 1969.

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