so my bird has a 85mph speedo. i am wanting to put in a 140. what do i need to do to make it work? also it has a 305 with a quadrojet. was told it was a pontiac motor. is it just a sbc or are the different? i am also wanting to install roller rockers as i am puting in a gear drive monday and new accel billet dist, coil and wires. is there anything i should do when installing rollers into a stock motor? has about 70k on motor. runs perfect. thanks