Stock Bottom End 5.3 LS Is Shattering Records
Records are falling with this stock bottom end 5.3 LS-powered Foxbody.
But, just how much abuse can the stock block take before it blows? We all know that truck motors are absurdly strong when it comes to throwing performance parts at them. The iron block truck motors actually do quite well with boost, but of course there is a limit to that. John Capizzi doesn’t mind living dangerously, when he plucked this 5.3 out of a truck and put it in a Fox Body Mustang, he decided to leave the bottom end alone.
Additions and changes to the L33 motor include a S485 turbo, Holley High-Ram intake, slightly modified heads, and of course, a custom cam to match. Boost is set to 32 psi and with relatively little head work, it tops out at an astonishing 8,000 rpm.
Pushed along by a Powerglide transmission, this setup is good enough for 7’s. Johns fastest runs in the video above were safely in that range, but a 7.81 @ 172 pass was completed by this monster.
After over 100 passes though, the inevitable happened. Sure it’s safe to assume a stock bottom end 5.3 would have an epic failure with that much boost, but truth be told, it made over 120 passes and was consistent enough for Capizzi to dial in the car for that record-breaking 7.81 second pass. And he’s not done breaking records yet. He plans to do exactly the same with a 4.8.
