How to modify your car without ruining its value


It’s yours. The car you’ve dreamed about, researched, obsessed over, found in superior original condition, or maybe even spent years restoring to make it perfect. Maybe it has even won awards recognize its originality, the way experts agree it should be, down to the number of threads on the valve stem caps that hold that de-ionized air inside correct one-year-only tires.

This is a companion discussion topic for the original entry at https://www.hagerty.com/articles-videos/articles/2018/04/30/how-to-modify-your-car-without-ruining-its-value


*Cars whose OEM radiators with plastic endtanks can be switched with aluminum versions that are often more efficient. OEM’s are easily saved.
*Early emissions equipment that’s power-robbing and trouble-prone can often be removed and saved.
*Bigger, more efficient intercoolers.
*Wheels and tires for more modern look, size and performance are easily changed. Not sure how it works or for how long, but I’ve heard of owners wrapping tires in plastic and storing them in a dark room.
*Modern lubricants


Tire storage can be tough. Even if tires are stored properly for a long time I still view them only as a show piece rather than something to be driven on. It’s simply a safety issue for me, the damage a blown tire can cause is far too significant for me to risk it.

Modern lubricants is a great point. No need to deny your beloved engine or drivetrain the advancements that chemical engineering has accomplished since the car was produced.


With the “Smogers” of the late 70’s and into the 80’s that were ‘dogs’ and an 85 MPH Speedo, can they be made to perform without radical mods that one can see? Ans., ‘Yes!" Ex., 1979 Hess and Eisenhardt Eldorado Convertible. Came OEM with an Olds 350 gas V8, ‘Y’ Block. Rated sea level H.P.? Try, 175. Ugh! One of the biggest reasons these vehicles are such low H.P is because of the low compression ratios. Usually around 8:1. So what did I do to wake this car up? (1) Installed a full roller Lunati Mild Roller Cam. Plus roller lifters and roller rockers. Necessitated tall valve covers that I modified to accept the PVC Port. Changed the nylon timing gears to a Double Roller Cloyes, True Roller timing chain. Installed 1984 Olds 307 heads with 68cc combustion chambers to boost compression. Original heads had 84cc combustion chambers. Also bigger valves w 2.0 intakes and 1.62 exhaust valves. Polished and ported the heads and port matched to the intake manifold. Installed forged domed pistons (stock bore). Resultant compression ratio? 10.5:1 Yes, you must use High Test Gas. Installed an MSD ML6 Ignition Box behind the firewall. Changed out the old pellet type catalytic converter for a new free flow (emissions legal) Walker Stainless Steel one. Ran a set of dual exhaust because I think they look cool. : ) Kept the smog pump and EGR. I.e., all the original smog equipment except the original Cat. Removed the weak TH325 trans and replaced it with a TH425 out of a 78’ Olds Toronado. Total results H.P. wise? Slightly over 300HP. : ) Best? None of it is ‘visual’ and the car still passes emissions both visual and tail pipe test. Now I just have to try to figure out what to do about the stupid 85MPH speedometer?


I’ve upset many a car owner that brags how “original” his car is when I’m standing there looking at pristine paint, albeit original factory color but an obvious repaint, and inform that owner that it is only original once and he can’t say that now. They go on to brag about how they used all manner of “correct” factory bolts and I repeat myself. It’s only original once folks. But I will tell them with all sincerity that while I appreciate the effort it took to REPLICATE the original factory work it was lost on me because frankly I don’t care. As many have said it is my car and if I want to bolt a Rolls Royce flying lady to my pristine '66 Chevelle SS396 I’ll do it! (((FYI…that Chevelle while indeed pristine, is NOT factory original…but it is a 138 car.)))