1/8 mile

Ok so i have a drag mini bike...15hp with a tav2 12t. After install i know i need stiffer springs all around. I still have stock doodlebug rear sprocket (70t). To get more top speed would i go up in rear sprocket size or down? I plan on running bike in the 1/8 and before i installed tav2 i...

I estimate im making around 11hp..I know thats not alot but its just a start. Right now I have a 15 tooth clutch with a 70 tooth sprocket. What rear sprocket would give me max top speed in 1/8 mile? My weight is 215lbs