I think the bigger argument for an engine swap (or even going electric) is to have something that is:
- reliable
- repairable
It is getting increasingly difficult to maintain our cars. If you need expertise then it's either already retired or about to.
I am now on my 3'rd mechanic as the prior 2 are in retirement. My current guy should have been retired several years ago, but he enjoys coming to the shop.
Specialist work is increasingly hard:
- Gus Pfister (Pacific Fuel Injection) is about to retire (or might have already, I got a pump done by him and chatted with him ~9 months ago).
- Metric Motors will have changes coming as some staff will retire in the next months
Even if you can wrench on your own, parts availability is a pain:
- I needed a oil pickup for the engine. None available from Mercedes. I got the last one from Metric Motors for a very premium price (it was their last one, and without it nothing would work).
- I needed a refreshed torque converter. Took me several months to source one. One supplier in the Bay Area has a new old stock steel one and they will sell it to "to an originalist who is willing to pay crazy prices".
The 60's Mercedes engines were never good in hot weather. In many states 80+F is becoming the norm for daytime temps. Inland CA, Texas etc its much more. You can hit traffic on your way, with you then being stressed with overheating. Driving without AC is not an option, driving with AC puts undue stress on the engines.
You can be all original and have a pretty setup and put it into your garage and admire it. But if you want to drive it (and not take it for a sunday "walk", but actually drive it) then the technology is just too brittle and hard to maintain. It's a 60 year old design and I see nothing wrong with something more modern, more reliable, more easy to maintain and getting parts for it.
And the younger kids are totally into engine swaps. Just look up the "M103 engine swap" or "M103 turbo" on YouTube and you will be amazed. Or the M113 swap that Kwiek Classics is doing. I am considering it, it's just a financial outlay that I want to avoid at the moment.