Open up your map and look at the central park area in the downtown section of the city. There is one single road that runs east of the park and comes to a t-intersection. You will know it is the correct road as there is a clothing store to the northeast and a mechanic to the southeast.
Drive to the where the road dead ends and turn left (going north). If you continue heading north the road curves towards the east but beyond this is a parking lot. In this parking lot I have found constantly spawning Lassiter Series 75 Hollywoods which will net you $2800.00 at Derek's and also Berkeley Kingfishers which will net you around $2500.00.
This lot is literally due west of the clothing store (on the north side of the street).
EDIT: Location can be found here.
I no longer have this game and haven't played it in years so I can't provide additional information. Special thanks to Radiant Viper for providing the pic & link location.