<VV> Speedo Question

[Bill H.]

                                                               B"H
Hi all.  My 66 Monza came with two things among others:  14 inch wheels and a broken speedo drive.  I replaced the left front bearing cap and of course the speedometer started working again...I think the 14" wheels make the speedo reading pessimistic; it says 30 mph and I'm really going 40.  Anyone know if it's possible to re-gear the speedometer for 14" wheels?  Has anyone done this successfully?
Thanks guys...Bill Hershkowitz 66 Monza Sport Sedan 110 PG A/C