Vintage amps & power cords

Every time I power up my old McIntosh MC2200 amps - a pair running in mono mode, I can't stop to think about those stock power cords. The cords sticking out of my preamp and the amp in my other system look like fire hoses as compared to these cords and yet these amps are rated at 400 wpc as configured.

I completely understand the argument that the designers knew what they were doing but using this argument the aftermarket power cord suppliers should all be out of business.

Curious to hear input from folks with vintage gear and wondered the same thing, and what did they do about it.  

The aftermarket power cord suppliers should all be out of business in a rational world.  They prey on placebophiles.

Buy better speakers, room treatments, a better DAC, move your turntable to a different room (build it as an add-on to that nice listening room will build), do anything else that works...

I rotate 3 power amps, and one of them is a McIntosh 2105 that I've had for many years. It needed work a few years ago, in fact, it was time to replace transistors (!). I took that opportunity to have the technician put in new input jacks, as well as an IEC input so that I could use a modern power cord, and finally, modern speaker terminals instead of those awful terminal strips that McIntosh used for years.

As a result, I am very happy with the amp; more than I was before, and it is more convenient as well. I know that the resale value is shot, and I don't care at all because I'll never sell it.

I use high end power cords in my system and love how they improve the sound. My amp however has a captive old school cord and its an original custom job, I take perverse pleasure in the fact the pricetag was left on the plug, $.05 in bright orange. The amp sounds fantastic btw.
Roxy, can't imagine the value being negatively impacted as long as the work is good. I'd pay more for the improvements you've had carried out.  
Of course your attitude makes sense, but that isn't the way many people see it. Their admiration for a certain brand or specific component becomes perverted into a fear of making any change to it whatsoever lest it no longer be "original". These things are just electronics in my view, and if they can be improved or even just maintained to perform to their original specs, why not?
I think it's funny when I see a for sale ad here on Audiogon that describes the component as "unmolested", as if changing it is akin to rape. Some even brag about it never having been opened or serviced...after 20 or 30 years.
My intent was not to begin a debate about the virtues of aftermarket power cords. Personally, I know they do contribute to sound quality, especially in high current/voltage/power solid state power amplifiers. Impact on resale value aside, I would think safety should be a concern as well if the cord is no longer pliable. I also have a CJ Sonograph amp that could benefit from a (power cord) upgrade.
I've had my vintage gear changed to remove captive cord, and the results have always been positive. The safety concern on a cheap 40 year old power cord is very real.
Any gear owned by an audiophile who cares about his or her credibility among other audio geeks (non geeks really don't care at all) should have the thickest possible AC cable, and that cable should be visible so you can point it out. I have a water hose thickness cable to one of my subs that is completely hidden under stuff, and thus is kind of wasted…it doesn't "sound" any better than a more pedestrian AC cable…but still…this sort of thing is important. 
" Curious to hear input from folks with vintage gear and wondered the same thing, and what did they do about it. "

I've had plenty vintage components over the years. It's very common to upgrade to a removable power cord, rca connectors and speaker terminals. If you don't have anyone local, give Audio Classics in NY a call. They're the biggest McIntosh service center, and they have an extremely good reputation. 
maybe you can combine yours and Wolfs concerns, and get an IEC input, and attach a cheap thin cord...
Yeah man…the Skinny AC Cable Revolution starts…I bet a case could be made for "vintage" AC cords…"although possibly dangerous, old, cracked, perhaps rat bitten fragile AC cables are the way to go for an original sound…make sure your homeowner policy is current."
Curiously, almost all "vintage" cords appear to be two pronged. It this something to consider when making the conversion to the modern three pronged IEC type cord? 
Sorry I misrepresented the price tag on my power cord it's $1.45 not $.05 and it is a grounded three prong cord.
Jond, you have one of the best - it will equal any other power cord

(except in an industrial env. with lots of noise and very long runs)
Haha it gets electricity from my variac to my amp, beyond that I can't say what it does but for $1.45 my amp does sound great. :-) For full disclosure all the other cords in my system are Cerious Technology Nano Signature.