Not meaning to upset the apple cart here, BUT, almost no 35 spline axles are gun drilled, only 40 spline or bigger. Most axles are 4340 or better 9310 steel. Neither one of these material are harded thru, it's impossibe, so they are ecentually case hardened. So they are gun drilled before heat treating, therefore the case hardening is on the inside and outside of the axle therefore making them stronger. Quicker accerlation comes from a lighter rotating mass which is critical in drag racing. The ProStock guys are running titanium spools also to lighten the rotating mass, just as they are running titanium rods for quicker acceration.
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