QotW: What’s the worst mod you can make to a classic car?

1973 Datsun 510 interior
There’s purists and there’s everyone else. At least that’s how the purists see things. We don’t expect everyone to keep their JNC showroom original, but there are things that simply should not be done.

What’s the worst mod you can make to a classic car?

Our vote goes to upgrading the stereo — holes drilled for amps, wiring harnesses hacked, and worst of all, door panels cut for speakers. See the 1973 Datsun 510 in the above photo for example. It was an original blue plate one-owner car, but the owner decided to cut a big ol’ hole in a piece of un-patchable vinyl that’s now impossible to find. Sadly, this was all too popular a mod during the 80s and 90s.

What say you, dear reader? As always, the most entertaining or inspiring comment by next Monday will receive a toy. Click through to see the winner from last week’s question, “Who’s the Baddest President of a Japanese Car Company?

Soichiro Honda on a Motorcycle

Our winner this week is G Duncan, a former sales rep for American Honda. He posted several amusing stories about Old Man Soichiro that you should definitely read, but here’s one that sent us scurrying to Google to verify its claims.

(I was a sales rep for the motorcycle division of American Honda for 40 years, starting in 1970. Based on that experience, I also cast my vote for Mr. Honda. Here is an amusing recollection I have about him)

… In some ways this reminds me of Mr. Honda getting furious when he heard the chairman of GM making this dismissive remark about the CVCC engine (after both Ford and Chrysler had bought the rights to it in the summer of 1973): “Well, I have looked at this design, and while it might work on some little toy motorcycle engine… I see no potential for it on one of our GM car engines.”

When Mr. Honda heard this, he bought a 1973 V8 Impala, air-freighted it to Japan, designed and cast a set of CVCC heads for the Chevy engine, tested it in our own emission labs, then flew the car back to the EPA’s facility in Ann Arbor, and had it tested by them… where it passed the stringent 1975 emissions requirements. You didn’t mess with the old man…

And guess what? It’s true! Here’s a PDF of the actual EPA report. Omedetou! Your prize from the JNC gashapon is a Hot Wheels Super Speeders mystery pack Mazda RX-7!


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63 Responses to QotW: What’s the worst mod you can make to a classic car?

  1. cesariojpn says:

    I had written out a lengthy rant filled diatribe about how modifications in any way are bad, but short, simple sweet kinda ruled out in the end.

    The worst car mods……is anything that didn’t come originally from the factory or approved tuning firm. End of discussion.

  2. Ryan says:

    Simmons on an RX3 with candy red paint


    f*#!@# STRAYA!!

    • Ryan says:

      That is the worst offense, poor rotary…. Ozzie sex spec nonsense.

    • RdS says:

      whether you like it or not, its a classic look for early rotaries in Australia.
      The style has been popular for YEARS – and no doubt saved a ton of early Mazdas from been crushed long ago.
      More often than not its done very well too; with lots of work, care, and attention to detail. its never half-arsed.

      Its may not something id personally do to one, but I definitely love to see them around.

  3. Nigel says:

    Fold out table sized GT wings and canards.
    Its ok to put one on an R34 used for time attack, but if the car will never gets past a “100” it serves no purpose.
    ( People do not use these anymore much, thankfully).

  4. Benjamin says:

    The worst mod one can make to a classic car is the wrong choice of wheels. The wrong wheel choice may not be irreversible as gaping holes cut in door panels for some hideous Sony XPlod speakers, but the statement is the same; this old car is soooo dope now that it’s rockin some 18″ Rotas.

  5. R134 says:

    I have to agree with the original rant by Ben… I still, to this day have to deal with horrible audio because the owner before cut away the original speaker mounts and installed speakers in the factory cardboard paneling (doors, rear panels, pillers, etc). I am in no way a purist, I love modding my j-tin but don’t mess with what works. 6x9s don’t belong in my ’79 corona, and no you can’t fit 6.5″s in the door. This was the case in all old yotas I own(ed): 86 pickup, 86 4runner, 79 corona, 79 pickup… I had to re-wire, install factory size speakers, and in some cases do interior sheet metal work for factory location speaker mounting.

    A close second: wheels 17″ or larger when your car originally came with 13s. I saw 17s on an 82 corolla… it wasn’t lowered (as if it would help) and it looked like a wagon on Oregon Trail.

  6. Aaron says:

    Anything you can purchase at a “car audio shop”!

    Neon lights, amplifiers, subs, mirror tint, fender vents, etc are all horrible additions to most any vehicle. But the number ONE, absolute WORST mod that can be done to a classic car is the addition of “screens,” of any kind. That includes: navigation, tv or dvd players, the dreaded flip-out head unit screen, the headrest screen, and anywhere else people are mounting these things.

  7. John M says:

    Roof racks! When I look at a car, the lines and stance are what appeal to me. Nothing throws that off more than a roof rack. One JNCer wrote about crying when he saw one on a Z32 – I fully understand his pain.

    • Brad D. says:

      I disagree with this, while roof racks added for looks are stupid, I run racks on my cars for the added utility. I like to mountain bike and kayak….I dont like putting a muddy bike in my car and certainly cant fit a kayak inside! So since I daily a nostalgic, the roof racks are a must.
      Besides, they are not permanent and can be taken off at any time.

  8. Derek says:

    DIY convertibles. Particularly on uni-body cars (as most of our nostalgics are), it will destroy the body stiffness and consequently the handling. It’s obviously non-reversible, it make something scrap yard ready out of what could have been.

    Runner ups for me: chop tops (gross), repainting with modern colors/metallic paint.

  9. Arend says:

    rear windows, tinted limo black…
    …those how doesn’t stick well over the lines from the defroster

    unfortunaly very comm’n here in Europe

  10. Mister Totem says:

    The WORST modification you can do to a classic is..

    improper FENDER FLARES.

    If you have a clean rare care.. in most cases you can find “eventually” another door panel, dash, etc..


    no coming back from that..

    now wheres my hotwheels toy.. hahha

  11. DirtyRice says:

    There’s ugly and then there’s unsafe. Yes, the irreversible damage to vinyl pains me deeply. But when integral parts like the motor, suspension, or brakes are compromised, then the vehicle becomes a potential danger. Combining new technology with old components can become quite tricky even for a skilled professional. So while gaudy rims and terrible paint jobs may cause me to throw up just a little in my mouth, it also makes me wonder about what I may not seeing.

    In general, any modification done improperly is bad. But the worst kinds are the ones that risk your safety and the safety of others on the road.

  12. GEN2TWINCAM says:

    The WORST:
    Non-Period wheels!
    This goes for our cars, American classics, and Hot Wheels models!

  13. Dallas says:

    I think the absolute worst modification you can make to a classic car is bosozoku mods. Personally I think that classic cars should be kept as original as possible. I especially hate seeing perfectly good Hakosukas with holes drilled into them for massive fender flares and missing bumpers and headlights with hoses coming out of them and awful engine swaps. Unless those parts are unfindable/unsalvageable why would you cut apart a perfectly good car? Bosozoku may be a cool, unique way of styling your car so it stands out, but you are defiling a perfectly good car that could be worth quite a bit of money and could be passed on to future generations to enjoy.

    • dickie says:

      yeah, every time i see one i feel that $60,000 or so burning a hole in my pocket that i could have used to save that car from the current owner.

  14. dickie says:

    my go-to answer would be wheels, as any car can be made or ruined by its owner’s taste or lack thereof when it comes to the decision of what to roll on. but wheels shouldn’t be considered a “mod” by anyone capable of changing their own oil.

    so instead, i’m going to go with something totally irreversible: convertible conversions. Japanese manufacturers have a history of reaching out to competent coachbuilders to produce topless versions of their sportier models. then again, you also have plenty of examples of cut-n-shut hackjobs produced by less reputable “shop’s in the back”-type operations.

    for every legitimate conversion you find, some extra digging will probably turn up at least a few “unofficial” examples created by or for someone with the same desire for a sporty drop-top but without the requirements for build quality and structural rigidity. many forgo body-strengthening reinforcements, some even neglect to provide any sort of cover for the occupants after removing the factory roof!

    if that weren’t bad enough, there are individuals out there who absolutely MUST feel the wind in their face and the sun on their shoulders while driving their classic Japanese car, and they won’t let the fact that their vehicle never came topless (factory or otherwise) stop them. fueled by these aspirations and probably more often than not some form of mind-altering substance, they will attack their mission with a single-minded devotion and a sawzall to create something that can never be undone (or unseen).

    so your bad fender jobs can be replaced or at least covered with a good set of flares. bad audio installs are straightforward to remove and repair/replace. but try accounting for a missing greenhouse… if you can find a donor with a good body north of the beltline and your welding skills are up to par, you might just be able to pull it off.

  15. Ken says:

    The worst mod in my opinion would be blasphemous motor swaps with chevy/ford motors; ‘to be different’ or ‘easy power’ is not a valid reason to rip the heart out of Scarlett Johansson and replacing it with that of a Gorilla. Is the output more? Yes. But now you gone and turned something gorgeous into a monster.

  16. Mike says:

    To me it’s anything that isn’t fully reversible. On my own car I have made a number of modifications, but they’re all 100% reversible, and that’s key to me. I have JDM Celica XX, and it was the most original one I could find. I’ve since repainted it (exactly the same as original) and done some suspension and engine mods, and everything except for the exhaust (which was rusted to pieces) is 100% able to go back to standard. I’ve got all the original parts in storage ready for the day I decide to sell.

    I want to upgrade my stereo sometime but I need to do that in a manner that I can reverse, so that’s going to be a real challenge, but I think that’s also part of the fun of owning such a car, making changes that you want to, without doing irreversible damage to the car.

  17. mikeyee says:

    people that slam their cars without taking the necessary measures to keep it “road safe”.

    the intentional “rust” look… >.<

  18. Big Mike Muniz says:

    Wow! so many experts on this site… I have lived and visited different parts of the world. You ask “what’s the worst mod you can make to a classic car?”. Well there are no right or wrong answers to this. It really depends what country you live in and where you are from. For instance, the RX3 that was posted by Ryan. That car may not appeal to us here is the states, but in Australia and New Zealand that is what they like. In different parts of Japan, vehicle styling also changes. I’m personally from the Philippines (born and raised till I came SoCal when I was 17years old). JDM styling is what is considered the only way to mod your classic Toyota there. I myself did that for a while, all my Toyotas had either TRD or TOMS period correct parts. Then I went to the dark side (at least that is what my Toyota buddies tell me) and dropped a Rotary in one of my TE27’s, does that make my car less worthy? Well maybe for the purist…But I am far form being that, I’m a car guy. I like all makes and models…import or domestic. I may not like some of the over the top mods I see, but I appreciate all the hours spent to make there ride just the way they like it. I do agree that the right set of wheels make the car. But then again that also depends where you are from. For example, my friends from Puerto Rico love WELD drag wheels on there KE’s and TE’s. One of them bought a 73 TE27 with WAT’s on them, he quickly took them off and gave them to me so that he can slap on a set of Draglites (and no, he is not a drag racer). That’s my 2 cents…

    • Mike says:

      “but in Australia and New Zealand that is what SOME PEOPLE like.”

      There, FIFY……..

      And isn’t that just the thing, there are so many different tastes all over the place, even in the same country there are different attitudes and tastes as to what is good.

    • cesariojpn says:

      No, there is always a right and a wrong answer. The thing is, modifications can be the wrong answer automatically via shoddy craftsmanship or improper part placement.

    • Ryan says:

      I’m from NZ, and that particular style of RX3 is thankfully fading fast (generational thing) in favor of Japanese style of customizing.

      Thank god.

  19. Knoonz says:

    I’d have to say oversized wheels are close to the top of the list for me. There’s no reason to put anything bigger than a 13/14/15″ wheel on a classic J car unless it won’t clear the brakes. To me there’s nothing cooler than fitting a set of 13s that are almost as wide as they are tall. After that it’d have to be swapping in modern engines. I get that people want reliable/powerful classics, but I feel like by ditching your carbed L24 for an sr20 you’re really sucking the soul out of the car.

    Mister Totem also mentioned fender flares above me, and this is a topic I always struggle with. I personally love bolt on flares, but it certainly does hurt to cut into that original metal because you know it’s not coming back!

  20. Nakazoto says:

    Swapping a carbureted engine for an EFI engine.

    Carbs are like Dizzy Gillespie and EFI is like the Version 1 Toyota Partner Robot. They both play the trumpet, but only one of them gets your heart dancing.

  21. Eljay says:

    I’m not a purist at all,but making an electric car out of a Toyota 2000GT is pretty horrendous!

  22. norman521 says:

    Body kits

  23. Sideglide says:

    I can sum it up in three letters: A P C. This stands for American Products Company. They mostly came into their own hideous fame with the cars from the 90’s once Fast & the Furious hit the theaters and cars started to hit themselves with understeer. That was all well and good to see seat covers with blue flames on a 92 Mustang, but then APC started to work it’s way into classic cars too. Now all of a sudden, classics started sporting “performance” clear taillights, billboard-sized vinyl graphics of laser jetpacks, and chromed out Monopoly token shift knobs. This company single handedly sucked the charm out of classics. Hand me down mint 510’s from grandma suddenly had stainless steel wings and wood sideskirts. RT40 Coronas now were sporting plastic chrome-colored door seam liners. The worst part of all this: original parts were chucked into the trash bin because it was “old”.

    I’d take a matured brown interior over one emblazoned with catch phrases and dragons any day. Take back the classics!

  24. datto410 says:

    plastic-fantastic FENDER FLARES…

    why would any sane person randomly cut their beloved j-tin with a crap 10-in-1 $25 tool from their local hardware store, and then proceed to screw in plastic-fantastic fender flares..? its beyond me!

  25. Moominsean says:

    Aside from anything that comes from an auto parts store, like plastic rims and bad steering wheels, etc., I’d have to say my least favorite mod is slamming the car to an inch from the ground. Nothing makes the ass of a kenmeri look fatter and more ungainly than dragging it on the asphalt. Nothing wrong with lowering a bit from factory, but I just don’t dig the super low riders. And I would agree in general with poorly replaced sound systems. Ugly speaker boxes and holes cut out of door frames just bothers me. The Corona I used to have had wires everywhere and a rotting box in the back window, as well as holes cut in the plastic kick guards for cheapo speakers. And the previous owner kept the “new radio”. At least he had left the original in place and it still worked when I rewired it. And I have a car coming over from Japan soon (more on that later) and in the photos it has a radio stuck in the lower console that doesn’t even fit…i sticks out an inch. And it has the ’80s speakers in the back window. No side speakers fortunately, and the original is still in place. Though I have no problem with putting in something unobtrusive for better tunes in your jnc…just keep it on the downlow and don’t tear up original parts.

  26. graveltrapp says:

    Running a close second to the previously mentioned stereo hack, I think that swapping another manufacturers motor is a bit sacrilegious and should be considered grounds for instant forfeit of the vehicles pinkslip as well as replacing the powerplant back to the correct DNA lineage.

    • Big Mike Muniz says:

      I’m sorry to hear that, I don’t limit myself to that kind of thinking. Not all car guys are “one” brand owners. Some cars are modified to take advantage of certain things. In my TE27’s for instance, I have had several “Toyota” engine swaps in it, but my monsterport 12A rotary engine make the car balanced on the race track. Even Toyota took note of the ” NOT CORRECT DNA” advantage by using another manufacturers engine in their new vehicle (FRS with a Subaru engine).

  27. Bear says:

    For an bunch of enthusiasts, there’s a lot of contradictory points in these comments. Just because you don’t think it’s right, doesn’t make it so….. So because you don’t like it or aren’t willing to understand it, it makes it a bad choice?

    It’s taken me awhile to get to this point but if you are truly an enthusiast, you appreciate the time and effort that’s gone into the build. Just because they used cheap tools and parts doesn’t mean they deserve to be put down because your a self righteous twat! They’re still making the effort to build the car THEY want.

    Don’t build a car to fit in… Build one to stand out!

    • Moominsean says:

      Making irreversable changes and then using crap parts or doing a crap job of it is painful to see. But, in the end it’s your car, do what you want to it…obviously someone likes it or it wouldn’t have been done. But this post is about opinions, and there is no shortage of those on the internet!

  28. Aaron says:

    52 QOTW’s per year, average 10-12 post per Q.

    Form a question to pose a negative response…. suddenly everyone’s keyboards work just fine.

    Love it!

    So far, my choice for winner is the intentional rust look, by mikeyee

    • Nakazoto says:

      I think it’s less about everyone wanting to type something negative and more about hitting a topic that everyone can participate in. Not everyone is familiar with who the president’s of car companies are or can comment on video game JNCs.

      Everyone of us loves old cars and can appreciate the work required to make them run, though. We all have opinions about how exactly each and every car should be built and all of our opinions differ. This is one of those rare topics that everyone can participate in, no matter their nationality, trivia knowledge or anything else.

  29. Brad D. says:

    Every time I buy a new car I think…this will be the one I modify, this one will get the motor swap, this one will get the ridiculous suspension, this one will get…………
    Then I drive it. I love it as it is, the feeling of driving something that was the way it was thirty, forty years ago is pretty cool.
    I don’t begrudge those that want to do these things to there own cars, and I have no problem with wheel swaps and bolt ons that can go back to stock. I know I have done these things.
    If you start with a nice clean car….leave it that way, preserve it for all the future generations to drive as is. Personalize and enjoy. If you pull it out of a field and save it from certain death, do with it what you want!

  30. Tyler says:

    Nakazoto mentioned it, maybe others, but the worst mod is “upgrading” the car to clone a higher trim level. If you want the expensive car, buy the expensive car. But don’t hack up perfectly good sheet metal to give it what it wasn’t meant to have.

  31. Bones in AK says:

    Anything you do because it fits someone elses view of what you should do to your car. I have had 5 510 2 doors with many mods that some people liked and others hated but each done how I wanted it at the time.

  32. longboy says:

    I like the comments about ireversibility, it’s a major factor when it comes to bringing a car back to life or overlooking as too hard and letting it die. Any mod that ultimately drives a car to be off the road and on a deathbed is a bad mod. (Too hard to reverse, too much police attention, too hard to legally register)

    worst mod: someone forcing the damn wrong sized nuts/bolts into a thread and then cross threading it like a bi***. CURSEE YOU ALLL

  33. Ken aka OkieRA29 says:

    I will echo others, I think that the worst mod you can make is a badly done one. I don’t have an issue with most mods, as long as they are done well. Any mod done in such a way as to compromise safety or structure is a bad idea. I have lowered my Celica, but I did it right. Shorten struts, proper inserts, coil overs and shorter shocks. I wouldn’t say that I prefer ‘tasteful’ mods as I like Bozo stuff, but ‘thoughtful’ would be better.

  34. 47hako says:

    Anything that brings discredit to our culture. Everyone has done, or in the very least, thought about doing one, more, or all of theses mods in one sense or another. There are ‘Purists’ that insist on originality, ‘Trailer Queens’ that go for every mod in the book, and ‘Track Stars’ where performance and experimenting is over everything. Each sub-culture has their own fair share of wannabe’s that go the wrong direction and execute poorly.

    The worst…the person that jumps on the bandwagon, doesn’t know what he/she wants, takes a little from all 3 categories, has a lot of funds, and executes poorly. The person with no vision.

    Can selling your car be considered a mod? No. But selling her to the wrong person can produce horrible results. (Dedicated to my once owned pristine ’89 MR2, Rest (rust) in peace.

  35. Nick G says:

    Lambo doors is the absolute worst. I don’t know when people decide that doors that open to the side are no longer cool. I would say that the same people fantasize about sliding doors on a mini van, but that would be disrespectful to mini van owners. Maybe they don’t have enough room in there garage to open there door to get out and while watching fast and the furious and perusing ebay they stumble across the lambo door kit and say “lambo doors will fix all of my problems. I can open them in the garage and they don’t open to the side”. Thats so dope!

  36. Tom Westmacott says:

    Almost any mod *can* be done well. After all, manufacturers produce lowered versions of cars, cars with aero kits, convertibles, a variety of wheels, different body styles etc, etc. If something is done to a truly high standard, it tends to work fairly well and to look good.

    Equally, any mod *can* be done badly – cheap parts, parts that don’t fit properly, poor preparation, badly fitted parts, general bad workmanship that leaves the poor car less reliable and less fun to drive than when it left the factory.

    So for me good mods are all about going the extra mile, thinking things through and doing them thoroughly and properly, so that they work as well as stock. IMO it’s not about good or bad mods, but mods done well or badly.

    • longboy says:

      so true, i’ve been guilty of making my car worse than standard lol

      lowered it – rides so stiffly on normal roads
      wider wheels and tyres – tracking and bumpsteer galores
      more powerful engine – drinks more fuel
      full exhaust – droning and headaches

      sometimes you just wish you didn’t bother but then you start hammering on it in the twisties and its like YEAAAHHHHHHH

    • datsungirl says:

      Thank you Tom,
      A quote that is a reminder for me:-
      If a job is worth doing, it’s worth doing well.
      If the attitude is not doing your best then don’t even bother, leave it to the professionals…lol
      Cheers:) datsungirl downunder

  37. Tofuik says:

    I’m fine with a lot of things. Hell I love most of the things the JNC proper don’t agree with, but I fucking hate one thing more than any other thing in this whole car modification world. “Altezza/Euro” taillights. I didn’t mind them on the Altezzas, but those fuckers spread like a disease to every car and truck on this planet. Import and Domestic alike have been afflicted by this terrible menace. Remember kids, only you can prevent altezza tail lights.

  38. ebrmc510 says:

    i know im chiming in a bit late but… cut in sun roof.

  39. datsungirl says:

    Commonly done with the Datsun 1600/510 1968 to 1972 but a immense cursing on any classic.
    Dissection and extraction of key components from the front end!
    Isn’t the first element usually seen on a vehicle the beauty of its face, the lustrous gleam of chrome, crystalline glass and glossy insignias?
    Discarding the grille, bumper bar, radiator support panel, etc. to forge room for an oversized and unnecessary intercooler/radiator setup.
    The Result:-
    – Visually grotesque
    – Structural compromise of the vehicle
    – Stripping the character and dignity from the original fundamental look
    – Most importantly mutilating the “face” of a classic vehicle into a repugnant monstrosity!
    If you have ever thought about doing this, please don’t.
    If you have done it, please change it back.

    From the undying classic car enthusiast – datsungirl downunder

  40. Brian says:

    I know Im late, but the worst mod you can make is one others cant respect all of the effort and money you spend on it, no matter what opinion they have on it. Meaning, its your property, and whatever you want to do with it is fine by me.

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