Curiously, a number of motor bits interchange between the SRX, XT, XT-E 600 and the 660 also. We had occasion to try a few on the racebike. I wouldn't be surprised if many more would also work if you happen the have an old donor engine.
The mechanical tach drive from the SRX bolts right on the end of the 660 cam, just pop off the cover plate on the right side! Why? Well, we had a PVL magneto ignition on the MZ, therefore no electrics for a tach, plus a pile of SRX parts
Later went to a self-contained Scitsu tach, and buttoned the cover back on.
L side cover gasket. Probably many o-rings, seals, gaskets. Someone mentioned the oil filter already.
Many gearbox parts. CLutches, primary gears etc interchange...although you usually swap the 660 stuff to the 600
We use an XT-E (late model) 600 5th gear in the 660. Has a slightly lower ratio than the MZ overdrive, but less extreme than the Slipstream C/R 5th, which we used at first. We set our motor up with a very long intake tract, and relatively small carbs for a radical 762cc motor, resulting in huge torque and a very flat torque curve, so the short 5th was more of a nuisance on many shorter, tecnical circuits...hence the compromise XTe600 5th.
I seem to recall that we used an SRX slotted cam chain sprocket in the MZ. A perverse bit of trivia: you can put a 4 valve intake cam in the 5 valve motor and the intakes all open after a fashion...but I can't imagine what the wear pattern on the cam-followers would look like, or how long before they slid off the side of a cam lobe and destroyed the top-end
I believe the intake tracts on the 600/660 line up, if you wish to mount race carbs. (Not too uncommon, I guess...we mounted a set of Keihin FCR carbs from an early Speed Triple we had raced right onto a fuel-injected Triumph manifold on a newer Speed Triple to fit it into a different class!)
MZ 660 countershaft sprocket not listed by aftermarket providers in the states, but the XT-E 600 (later electric start model) countershaft matches, NOT the 660 Raptor. 14, 15, 16t available through Sprocket Specialists, Afam. I use a 17t C/S ( yes you can fit one on) but had to get it from Talon in the U.K. (17t is needed w/larger rear for swingarm clearance on the racebike when the rear gets jacked up for correct ride height)
Has anyone tried the exhaust from one to the other? The headpipes on my old SRX appeared the same, but I never tried it.
Oh yeah, Raptor head gasket set fits the MZ too...strangely, not too much else does. I can vouch that none of the gearbox does.