did a search and was able to find a torque specifcation for spark plugs for a 112 engine. 28nm and, if my conversion is correct, 247inlbs. question. this approximately 20ftlb figure hold for the engine in an 89 300e? working on someone else's car and do not want to screw up. thank you.
p.s. will be using a bean type torque wrench calibrated in inlbs.

A quick, yet accurate way to convert Nm is to take 3/4's of that value to get ft. lbs. 20 lbs is pretty close.

I have always torqued my plugs(M103) to 15 ft. lbs just to play it safe. To date this has worked fine.

My 2 cents.