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

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Zachary
Dallas, Texas
Software Contractor
1973 450 SL
1977 Silver Shadow II