raycasting without colliders

I am making a voxel based game which is near completion. The main problem I have is raycasting as I have removed the mesh colliders for speed and so am using a custom solution which is incredibly inaccurate. So, if anyone has a solution please tell me and I also have the 3-dimensional array for data. Here is the code I currently use-

     public static bool Raycast (Ray ray,out RaycastHit hit,float dist) {
         for(float i = 0;i < dist;i+=0.5f) {
             Vector3 rDir = ray.GetPoint(i);
             if(isSolid(rDir)) {
                 hit = new RaycastHit();
                 hit.point = rDir;
                 return true;
             }
         }
         hit = new RaycastHit();
         return false;
     }
     static bool isSolid (Vector3 pos) {
         return (worldGen.Block(pos) != Blocks.Air);
     }
 //WorldGen.Block
     public static int Block (Vector3 pos)
     {
 return data[(int)(pos.x),(int)(pos.y),(int)(pos.z)];
     }
 

Thank You.