I did buy some 660 years ago to do up a pony. May need it soon. That was suggested to me by an old time machinist.
I have made bearings for D6 pony,same set up larger size. Bronze with babbit lining cast in and machined to size. Not really difficult and working for me. You may need to bore the housing slightly oversize and make a custom size bearing.
660 aluminum would be preferred and easiest on the crank journals.
I am still have a poney block 5f9341 for D2-D4
I am still have a poney block 5f9341 for D2-D4
You have one for sale or looking to buy one?