I have a 1972/1973 450 SL (Title says 1972 350 sl, but car has 450 sl badging, production date of May 1972) that I inherited from my grandfather and it is in need of some major engine work. The car has been sitting for over 10 years due to a small engine fire. I am in the beginning stages of trying to restore the car. It has been in my family since new and it is very special to me.

I have removed the original engine and transmission and started to evaluate them. The fire in the engine compartment was started by a "rats nest" that was on top of the engine. The car had been in stored in a warehouse at our family business for several years and my grandfather started the car and the big bundle of newspaper and sticks on top of the engine caught fire. The fire was put out quickly, However, it burned most of the wiring along the firewall and the top of the engine. The tops of the injectors were also burned.

As a result of the damage we simply let the car sit in place for 10+ years. My grandfather has since passed away and I am now in the process of attempting to resurrect the car.

I wasn't sure if the engine was salvageable or not so I started looking for a replacement engine. I acquired an engine and transmission from a 1978 450SL that only has 58K miles on it. I also found a new wiring harness.

I had a local mechanic that I use for work on my large delivery trucks for my business attempt to swap the engine and he said that he couldn't make the 78 engine fit into the 73 car.

I am looking for some advice. I have both engines and transmissions, the original is burned and has 140K miles on it, the replacement is from a 1978 450 sl and only has 58K miles. Can I swap the engines? If not, how difficult/expensive will it be to rebuild the burned original engine?




Andy

 

The two engines are identical in size but they have totally different fuel injections systems requiring different wiring harnesses and fuel system.

Yours is a 1972 350SL 4.5. It was originally badged 350SL but some owners and dealers changed the badge when the 450SL came out in 1973.

 

Wondering how your restoration project worked out. I am in a similar situation, 1972 450SL, family-owned and garaged for 10-years or more. I don't really even know where to start with this project or how much it will ultimately cost.