Sure there is, buy brand new tires with all their tread. Better mathmatically figure out what circumfrence you need first, as not all tire manufacturers, will have the same circumfrence for any given size. then you need to park your brick... leave it on jackstands or cinder blocks, depending on you geographis location so that there are no flat spots on your tires. This should give you the exact speed reading you are looking for, for about 10,000 miles that is, unless you have a lead foot like me. You will want to drive it once a month to keep the battery charged, fluids moving, and engine from seizing. Rest assured, your speedo will read accurately.

Seriously, manufacturers engineer in this speed correction on their cars. If you ask me it is an UNWANTED safety feature. Most manufacturers stick to 3 mph, which is right about where you are evidently, some have errors as high as 4 or 5 mph, as the quality control isn't what it should be on your lowes scale cars.

You could write the CEO of Volvo and tell him you want a dead nuts speedo in your next new brick or you aren't buying. Let me know how it goes.