I was fortunate to have that rare priviledge too, and agree!!

Thank you. I know the donor car because I have owned it for years. Of the three 300SDs I have owned, this engine was by far the peppiest. That said, it has a decent # of miles and leaks like a fountain pen. The scope started as "I'm just renewing gaskets and seals" then creeped to a full rebuild on the "while I'm in there I might as well..." principle.


True. My design goals have been confident peppy, never neck snapping. However, I feel like there's a chance the results may be surprising for the following reasons:

I recently received my 7.5mm "M" style custom built injection pump. I chose the "M" instead of "MW" style because is easy to user-adjust. As this group knows, the orifice size is *the* limiting factor of these injection pumps. I am not a fluid dynamics expert, nor completely sure of the shape of the orifice, but assuming it is a circle, the area of a 7.5mm diameter circle is approximately 86% larger than a 5.5mm circle.

The engine will get a Holset T3 HE221 7cm² turbo and a Saab Blackstone intercooler running through a non-EGR intake to burn all that extra fuel. Per the testing, and the experience of the OM617 swap groups I follow, that turbo allegedly spins up early enough to start boosting at 1200 RPM (vs 1800 RPM for the MB factory turbo).

Those two previous items are why I purchased ARP head studs, as researched and developed by Michael Anderson.

While the head is off, I take it and the specs to a competent machine shop and get the intake valve seats modded for a bit more flow. Someday, I will attempt porting & polishing, but that will be later, (and probably on a spare head).

The stock 380SL (and stock 560SL) comes with a 2.47:1 differential. This project is getting a 3.46:1 diffferential I acquired from a gently used 300SL. That should make the "seat of pants dyno" readings better off the line.

It will be interesting to see and feel what that combination of incremental improvements add up to in real life. If I can give a ride to a 560SL owner, and show them performance that at least generates the "RCA Dog" look of surprise, I'll call that a win, lol.

I do already have it. I know it is a little twisted, but I have put hundreds of 1000's of miles on three OM617's and I just LOVE them and didn't want to learn another platform. Also, thanks to @Idahobenz 's research and experience, I already have the rare engine brackets to just drop it in the R107 chassis. Ha - I have already made this project harder than @Idahobenz ever intended, lol.