If all factory your looking at probably 60-80k on the high end maybe more depends on what part u use nos or aftermarket an who's doing the work
1987 Buick Grand National GNX.
Arlington, TX
The Buick Grand National and GNX models were trim options for the Buick Regal vehicle. Production lasted from 1973 to 2004 and recently began again back in 2011.
Buick Grand National GNX.
Depending upon the year, it could say Regal, or Grand National. Most 1986s will say Grand National on the title. 1987 is particularly confusing, some have it, some do not. The best way to confirm that you have a grand national and not a Buick regal Turbo is to check the build sticker on the driver door or the trunk lid. if you see a code "WE2" in all the option codes you have a real Grand National.
5x4.75 or Metric 5x120.7
200
You can buy a Buick Grand National off e-bay. They range from $3000 to $30 000. Sometimes less and sometimes more. You just log on to e-bay, search for Buick Grand National and remember to add your area, and it will show you all those Buicks in your area for sale. Majority of them are used. New Buick's are bought from your nearest dealer.
Stock 130mph Custom 188mph
Buick grand national, Studebaker,
If that Buick has the 17 digit vin, the 8th digit would be the engine code.
I think it was the Grand National which came after it successor, the GSX