I purchased a 6.9 engine around 13+ months ago for a seperate project which went sideways. Found a few 450SELs without an engine so I grapped the engine thinking I could grab one of the two cars .... but, it went sideways. For the last 10 years I wanted a 450SEL 6.9 ... but, I am thinking I will just stick to my W123 and graft the HPN suspension system into it. I got virtually all the parts and figured out how to rebuild the struts. Just need a few odds and ends to have everything I need.

Had a mini-circus on CL trying to sell the engine. Engine has been on eBay for a while now. Actually sold it twice except the "buyers" never paid. So, it still sits for sale. I got it out of my driveway to my HOA's and wife's delight. It's on a stand now in my garage under its own lights for tinkering when I have an off moment.

My OM617 turbo engine is headed back soon from the machinst. I have my "super-turbo OM617" on the stand getting ready for some fininshing touches.

So, would a 6.9 really fit inside the engine bay of the W123? I would say yes. They look totally different but I am thinking it would fit. Another forum member says yes too. The problem is the tranny. Need to modify the tranny tunnel which I am not going to do. So, maybe a T-56 six speed from a corvette? That might just work ... not 100% sure yet.

So, any thoughts ?

The weight between the two engines is pretty close. Although it's a giant, a 6.9 is around 750 pounds and I can shave off at least 50 pounds without any issues or causing any real need for a mod. The fully weighted OM617 turbo is around 675 pounds. Does 25 pounds really matter? Battery in the trunk should fix that difference ?

Any thoughts on a hack oil tank? Fuel pressure PSI ? Mounting on a reinforced pallet with wheels so I can move it in and out of the garage is a must. Overall, without a huge investment of money, I am thinking I can get the engine running on a temp basis to see how it runs. I can get the aluminum plate pretty cheap for the T-56. I have a great machinist who could fabricate the plate and figure out the flywheel/clutch issues.

Any pictures of anyone really having a 6.9 in W123 ?????????

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