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Bear with me if this has been asked before! I have a 1978 500 motor that was assembled without the dowels that go in the front and rear engine mounts. I have dis-assembled the motor and managed to secure ,not one, but two sets of these dowels from 2 different continents.
Confusingly for me, they are different sizes. One set are 65mm and 25mm. The other set are 65mm and 20mm. Sooo, I’ve had a couple of people tell me that the 65mm ones are the ones to use in both engine mounts , but the combined length of both crankcase engine mounts are (front) 95mm and (rear) 104 mm which means that the 65’s will be 30-40mm too short. And where do the short ones go?
I hope someone on here can tell me definitively if I’ve got the correct ones and which ones to use.

Hi Cactus, use the 65mm dowels in both locations. They aren't meant to fill the complete mounting point, just centralise the two points on each case. If you look in the hole you'll see the dowels will only be a snug fit across the joint face, and the outer end of the holes are slightly larger. So as long as you drive the dowels in, across the crankcase joint face the job is done. The smaller dowels I haven't seen on any 350 or 500 yet but it may be somebody cut those down, to make two after losing a 65 mm dowel!

Thanks very much Steve. That explanation is the clearest I’ve had. All systems go now.

I have a picture of a crankcase albeit a 350 showing the dowels

Thanks 3potjohn,
I knew where the dowels go, it was all the measurements that were doing me in! Trying to make sense of not enough information. Steve Brown has set me on the correct path.