Thumper cams are simply ground with a reduced lobe centerline angle to give that particular low rpm rumble.  I recently installed a 106° lobe centerline Isky in place of a Thumper cam in a customers engine for that same distinctive sound while also seeing an increase in overall performance.  Be sure to look at the overall specs of a cam so that performance is not sacrificed at the expense of just having that race car sound.

Lorena, Texas (South of Waco)

  Was looking at Comp Cams web page and found a listing for their Thumper Series cams for the Ford Y-Block but no grind info,has anyone ran one in a y-block or info on how they preform?I'm running a Crane S-264-C regrind and like the sound at idle but would like a little more lope to it--any cam suggestions? KID