what you want is a program called norton Ghost. first create the partitions the way you would like them on the new hard disk with a win98 startup diskette. you can read about how to do this at
www.computerhope.com . just do a search on FDISK simulator.
when you use ghost to copy the partition to another hard disk you can have a different size partition on the other hard disk. let's say your old hard disk is:
40GB total capacity with:
10GB for win98 primary partition
30GB logical drive inside extended partition for storing data
and let's say your new hard disk is 120GB with:
120GB total capacity with:
20GB primary partition. you will use this to copy the win98 from the old hard disk
100GB logical drive inside extended partition for storing data
notice the new hard disk you are getting has a larger partition created that you will copy win98 over to it. install both hard disks inside the computer. run Ghost and do a partition-to-partition clone. choose the old hard disk's win98 partition as the source partition (partition win98 will be copied from) and choose the new hard disk's 20GB partition as the destination partition (partition the win98 disk image will be copied to)