Use the Thumper cam for the rhythm and the muffler of your choice for sound.
Get the spring specs of the Thumper cam since someone said (though I do not know) that the springs need head work to install and use.
Switch to similar Crane springs with the correct inside diameter to clear.
On my old build, I choose a Crane cam and there springs are a direct fit. BUT he sure to choose correctly!
Oh! The 318 can and will outrun a lot of Chevy 350's. Build wisely for such endevores. Make sure the car is light!
