Car modifications to consider carefully, according to you

We put the call out on the Hagerty Forums last week to tell us about the modifications and customizations you did on your car—only to regret it later. Customizing cars is a rite of passage and can be rewarding. There is nothing like being able to pick out your red coupe in a crowd because of the custom touches you have done.

This is a companion discussion topic for the original entry at https://www.hagerty.com/articles-videos/articles/2019/06/07/car-modifications-to-consider-carefully
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I have a 1968 Dodge Coronet 500 convertible. I wanted to upgrade the headlight to more powerful ones with a Halo. I was told the lights are a drop in factory fit. Ha! I had to cut out most of the light bucket and some sheetmetal behind them because they were too deep and the headlight retaining ring had to be enlarged to hold them. The lenses were plastic and fogged up… Total junk! Ended up restoring everything and bought some good old fashioned Halogens.

You forgot to mention hacked wiring in the stereo section, I can live with holes in panels, that is what plywood and Joan’s fabrics is for. A dash that looks like a Disco on a Saturday night or a car that will not start are unacceptable.

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I would say anything you cant reverse easily. By modifying a car to much if you ever want to sell or move on you have to find someone with the same taste which can be difficult at times. Upgraded safety like brakes is rarely frowned upon but body work beware!

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I have not personally done this to any of my vehicles but I think that lowering your ride is a very bad idea (especially trucks). Dragging your undercarriage over speed bumps and destroying your exhaust system are the least of your worries. unless your car comes equipped with adjustable double wishbone “A” arms you will seriously offset your tire geometry making it necessary to buy a full set of tread for your ride every few months.

I purchased my 1966 Corvette from a neighbor in 1970, which I still own. In the early years of ownership I craved having the rear wheel wells radiused and flared so large slicks could be installed. Didn’t have the $’s to do it back then and am thankful for that. The 427 BB red coupe remains 98.5% stock.

What really grinds my gears are the folks who install an aftermarket radio by first cutting the OEM connector off the vehicle’s wiring harness and then try to directly splice the aftermarket radio wiring into the vehicle wiring and make a total mess of it! Buy the adapter plug for your vehicle and splice the aftermarket radio’s wiring to that!


Preferred to start with driving safety by replacing drum brakes with disc brakes all around - great to go but better to stop when necessary.

Interesting the comment on not flaring the wheel wells on a '66 Corvette circa 1970. Thanks to the Corvette’s fiberglass body, this has to be the easiest, cheapest and most reversible modification one can make to car. With reversal MJ’s car would still be 98.4+% stock - and the repair would be practically undetectable. Back in 1970 Chevrolet even sold factory repair panels with which to make the reversal. The only thing that made it expensive in 1970 was the lack of body shops willing to work on fiberglass. This let the few that did venture into glass work to charge astronomically inflated prices.

I totally agree with the aftermarket stereo comments. My '79 M-B 280SL had at least three different radios as near as I can tell. This included three different holes in the door panels on a car where everything else was original. In the process of undoing this mess and re-installing the factory Becker Europa radio, I found and removed 20 pounds of amplifiers, graphic equalizers and random wiring up under the dash, none of which was connected to anything. There also was at least one uninsulated hot wire dangling up there. There’s a reason they invented the “hidden audio” stereos and low profile speakers that fit under the seats - for the sake of the next guy, use’em.

I have a 1965 Corvette Coupe, which came close to being totaled, which a battle ensued, with the insurance company, damage to the car was $1900 dollars which was the total out price on the car at the time 1978. At that time the fight ended with me keeping the car and the insurance company giving me a check for$1000, what I ended up doing was a full body make-over, Ecklers Corvettes made all of the panels and flares, done deal put t all together, fixed the headlights up, and had my as close to a Corvette Grand Sport, Would I do it again YES, I’ll never be able to get a real Grand Sport but I feel I have the next best thing, I still have the car and still enjoy it, along with my original 1964 Convertible, still over the hill but I enjoy and have the best of both worlds, 1 custom 1 original what else could ask for?

I have a sunroof that was installed in a 1966 Mustang Fastback when the car was new or near new. It is an electric steel sunroof that I believe was made by American Sunroof Company in California. There is a 1968 Shelby with the same sunroof that was in Mustang Monthly last year. I just need to buy a 66 and install it for the ultimate day 2 option.

Had a friend back in the '70s who installed an aftermarket sunroof. He found out that “Sunroofs” are called that for a reason. We lived in a climate that was not particularly sunny. The next upgrades he added were a bucket and a big towel to catch the leaking water.

Interesting that under-body lighting was so prevalent but not mentioned. I’d be too embarrassed too.

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In 1971, replacing the factory fuel injection system on a 1965 Corvette for a 4 bbl carb setup…AND paying the dealer to do it!!!

I was the benefactor when buying the car, the seller had large regrets…

This article prompts me to mention a modification that thankfully I DID NOT do. I bought a 1970 Porsche 911S coupe from orig. owner when it was one year old. I drove it for about 5 years in autocrosses and on race track DE’s. I got tired of the difficult 1-2-1 shift needed in autocrosses and a friend in the Porsche Club told me I could replace the original 901 transmission with it’s unusual dog leg shift pattern for first gear. The newer 1972 and later type 915 had gears 1-4 in the normal “H” pattern with 5th being the one out of the H. I thought it sounded like a great idea so at a swap meet, I bought a 915 tranny. Then I learned that to make room for the slightly larger 915 tranny I would need to beat on the underside of the hump between the +2 rear seats with a sledge hammer to create space so the tranny would fit. I never got around to doing that and happily sold the 915 for a handsome profit at a recent Hershey swap meet. My 911S remains stock and is now worth more than my house. Had I installed the 915, I hate to think of how many thousands of dollars the car’s value would have suffered.

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The Buick Skylarks in the sunroof mods header pic are actually GM factory Sun Coupes with the retractable sun roof fabric panel, only made in '72 and in very limited numbers, the super rare ones would be the GS Stage 1 Sun Coupes of which only 6 were made out of the total 3943 total Sun Coupe production for '72.

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Yes, I saw that picture and realized these were not aftermarket, but the rare factory sunroof cars.

I suspect the resto mods that are so popular today will be considered poor choices in the future.

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Putting a Chevy 350 into anything that is not GM product. Just because the engine is ubiquitous, easily modified, and most of us all learned the basics one of them does not mean they belong in Fords, Mopars, or anything imported (mind you anything imported that did not have one in from the factory that is)!