1981 380SL V-8 engine cross-reference
 

Hello! I have the opportunity to purchase a 1981 380 SL convertible with a blown V-8 engine. It ran out of coolant, so the heads are warped, cylinders are scored, etc. Just from looking at it, it needs completely gone thru. I also have the opportunity to buy a 1973 450 SEL V-8. It is in running condition. My questions are: Would this engine fit? If it would fit, are the fuel-injection systems compatible? Would the new engine bolt up to the original transmission? If this engine would not work, what engines would fit? Thanks in advance!

The '73 is D-Jet FI. The 380 is K-jet. Totaly different animals.

About the only way you could do it was if you had a complete 450SL for parts.

Your real cheapest real options are buying a running 126 of the following models with a good running V8. 380, 420, (500) rare or 560. The 380 would be the simplest, but the least desireable, due to the single row chain. The others are at least the same tech level and share common CIS fuel injection systems.

Frankly, unless you're just looking for a project, your cheapest and best option would probably be to purchase a complete running car rather than the SL with the blown engine.

Unless a later 380 dual-row configuration is utilized. I agree it would be the easiest path. As mentioned, you really have to weigh the worth of the end product when entertaining the amount of effort this project will entail.

Thanks for the replies! The car I'm looking at has never been driven in the winter, which in N-E Ohio is a huge bonus. It is rust free. If this car was driven in the winter, by now it would be a rust bucket, if not in a junkyard. It has 110K miles on it, a two owner car, and a couple of years ago had the timing chain converted to the double-row chain. It has all maintenance records. It is a very clean car. I have the ability to swap an engine- that part I'm not worried about. What I don't know is what other engine will fit in this car, hence my post. Wodnek- what years of the models you listed would fit? Again-thanks in advance!!!

8 grand buys you a long block... and a nice replacement car...complete. Your Choice.

The cheapest option in the midwest is to buy a good running 126 body that is rusty. In southeast Wisconsin I see them for $500 to a grand quite often.
The models that would be at the same tech generation would be a 420, 380, or 560. If you got really lucky a 500, but they are very rare here. These engines are all closely related. I think most of the 80s through 91 should get you a good donor.

If you are going to do a swap find a 380 or 500 sel for an easy swap. In 1986 MB changed the electronics on the fuel injection system making a swap a little more difficult. Dropping in a 450 engine would be a pretty big undertaking. Check this link out where somebody dropped a 560 engine into a 450sl. It will give an idea of some of the difficulties you may encounter in switching engines.

http://www.carcentric.com/MB2MBswap.htm

Unless somebody is giving you that car for free or you enjoy doing that sort of thing I would pass on it and look for a running model. SL's, sadly, are selling pretty cheap these days.

Thanks again for your input! The car is 3K, so that's the starting point. I can't stress enough how clean this car is, so I think it's a fair price. I need a winter project to keep me in the garage:D But I didn't want to buy it unless I knew what I was getting into. Now I do, and will start looking for a donor car. I will keep you posted....