I had a toploader, & 3.00:1 gearing in my car for about 7 years. I did two things to make the combination work. First of all I had a taller first gear added to the toploader when it was being restored by David Kee. This one:
2.90 First Gear
Component Manufacturing
Secondly I added about 80 HP +/- with the addition of a vintage Paxton supercharger. You can probably get the same increase by going with aluminum heads.
Z.