81 750 ignition fitted into 78 550

[Pewpew82]

Would there be any long-lasting effects of replacing the stock points on a 78 550 8V with a later electronic plate from a 750 16V?

After looking at the parts side by side, the only fit issue is the "lip" on the bolt head for the 750 parts.

Has this been done successfully?

[GregT]

First, you'd hope the locating pin is in the same angular position on the two cranks.
Second, the 550 ignition curve goes 15/1500 to 40/2400rpm, Where the 750 is 15/1500 to 35/2400rpm

So you'd advance the backplate 5 deg - and hope the extra advance at idle wouldn't kill your starter.

I'd make sure the timing marks are correct with a degree wheel then use a timing light.