Will the 700r4 fit 84 Chevy 305 small block?

Yes, a 700R4 transmission will fit a 1984 Chevy 305 small block, but it will require some modifications and considerations. It wasn't a direct bolt-in application from the factory in all cases. You'll need the correct bellhousing (specific to the 700R4 and the small block Chevy) and likely a new crossmember to accommodate the transmission's length. You may also need to address the speedometer cable connection and potentially the TV cable (throttle valve cable) adjustment for proper shifting. A professional installation is often recommended.