Good idea to put a 560 SL engine into a 450 SL?
 

I have a 1973 450 SL with 190,000 miles that needs paint and around $5,000 worth of mechanical work. I’ve had the car for 28 years and hate to let it go but I’m not sure it’s worth putting money into. How much are these cars worth in good condition?

I’ve been quoted $2,500 for rebuilding the transmission and the engine needs some work as well. As a 450 SL is underpowered, I’ve been thinking of replacing the current engine/transmission with one from a 560 SL. Would a non original engine/transmission lower the value of my car? Is a 560 SL parts car hard to find? Where would I look for one? Are there any issues to putting a more powerful engine in my car?

Thanks

A 450SL with 190K miles that needs paint, engine, transmission and probably steering/suspension work is basically a parts car, unless you can personally do the work and/or willing to spend more than the car is worth. You'd be lucky to get $1500 bucks for it as is.

In excellent running/driving condition with 190K miles on it, maybe worth $4000-$6000 dollars depending on body/paint/interior condition.

Forget the engine/trans conversion unless you can find a guaranteed decent whole swap car, can do all the work youself, have all the knowledge/time/space needed to successfully complete the job. Just not worth the effort IMHO. Forget resale value, it'll be a chopped car.

With lower miles and decent overall condition, you can buy a 560SL for under $8000. $10,000 will get you a nice car needing minimal work.

Sorry to say it, but I think it's time let her go.

Either a parts car or a cheapo sale on Craigslist to an enterprising DIYer.

It seems to me there is no economically sound reason to keep the car. That is not the same as no reason to keep the car.

Personally, if I'd had the car 28years and if I'd put all or most of those 190,000miles it, there is no way I'd be parted from it; nor would I turn it into some bastard hybrid 450/560SL. Rather, I would spend the $5000 on the mechanical issues and leave the paint as it is (unless the problem is rust) and look forward to another 28years with a car whose character I knew so well.

What I might do is strip out all of that emissions paraphenalia which chokes the motor (then it won't feel underpowered) and fit Euro lights and bumpers: I don't know how you guys in the US cope with those crazy modifications.

I agree with jjrodger. Sometime we have more sentimental reasons than economic reasons to fix up a car.
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Swapping different engines is a lot more complicated now that we have anti-pollution and fuel injection systems. Check this link out where somebody put a 560 engine in a 350sl and you will see it can be done reasonably easily but its not a weekend job.
http://www.carcentric.com/MB2MBswap.htm
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Your best bet is to get a complete inspection of the car done to see what are the major issues. If $5K will solve them and you're happy with car I would be inclined to go that route. It may sound intially a little pricey but if you get another 28 years of use out of it - that's $178.57 annually or $3.43 weekly - the price of two large coffee up here.

I was thinking something like this but you said it better than I would have.

Tom W

If I'm not mistaken, a 1973 model has little emission equipment. I believe model year 1974 was the start of the US federal emission requirements. Even if not so, it is a federal crime to strip out the emission equipment, punishable by heavy fines. In my state inspection, that's one of the first they verify, especially on older vehicles.

I agree that 28 years is a long time to be attached to a vehicle. For me, the deciding factor would be rust. If it has advanced rust the sentiment factor would out the window.

Those crazy bumper modifications might not look as good as the euro. vehicles, but they sure can save your ass/wallet in a <5 mph impact. Those euro. bumpers are basically decoration and provide virtually no protection. I guess it's a trade-off of looks vs. functionality. I've seriously considered the swap myself (and still think about it:)), but I've personally experienced :(:(the results of those flimsy bumpers in a low impact situation(hood, grill, radiator, etc....).

I understand the passion of keeping a car
a long time and not willing to part with it.
Ive owned a 1970 Datsun 2000 since 1976. Its
definately a POS but I keep it running good
and drive it around during the spring and summer.

Ive been lucky to own an '84 280sl 107 stick for the
past 10 years and that car has 190k on the clock.

I hope to keep these two treasures for the rest of
my life and grow tomatos in them when they
dont run anymore.

Sturg:D:D

Not to mention that a '73 450 has D-Jet injection, the 560 has KE-Jet, so the swap would require a donor car, and a lot of time/money.