As I’ve said before in other threads V/P does not make many of the components used, only specialized parts like for the drive, transom mount, certain cooling system parts etc. Engines are GM with ignitions usually being a Delco EST or Voyager system.
Why do you think you have to replace yours? Usually with these you can replace the module but sometimes what both Volvo and Merc do is make these parts NLA. So you wind up having to replace the whole thing when its not more than a hundred bucks of electronics that's bad.
This is why I stuck with a simple breaker points distributor, these can be maintained with a cap, rotor and points set you replace every few years. Auto shop 101.
I did some checking and it appears that you have the 'crab cap' model, you have to look around because that's different than the Delco EST/Voyager style distributors that used a standard cap. I'm not sure that the Delco EST style distributor can be substituted for the 'crab cap' models. On these units there is a module and a sensor that can be replaced separately, they are both in the range of about $300, you should do some diagnostics to see which part is bad, so there may be no need to replace the whole thing.
take a look at this:
http://www.volvopentastore.com/Ignition ... _id.783800not sure if this is your exact model but it is in the year range of yours. best way to look up VP parts is your engine model # which will be like a 5.7GIxxxxx.....G stands for General Motors engine, I is fuel injection I think.