Tag: SBC

Pit Stop: Why LS Engines Peak at Higher RPM Than Classic Small-Blocks – Marlan Davis @HotRod

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QUESTION
I have two questions I believe are related:

  1. Why do LS engines rev higher and reach peak horsepower and torque at greater rpm than a traditional small-block with similar cam-duration figures?
  2. Why do LS engines not seem to benefit as much as a traditional small-block from the addition of long-tube (equal-length) headers?

Jack Engler

ANSWER
Back in 1955, you (or your grandpa) might have posed a very similar question: “Why does that new-fangled small-block Chevy make more peak power and torque at a higher rpm than my trusty Flathead Ford?” The short answer: “Technology marches on.” Broadly speaking, modern Gen III–and–later LS engines benefit from nearly a half century of progress since the original small-block’s debut, many of which are thanks to the tribal knowledge gleaned by racing traditional Chevy V8s. Racers demand efficiency, but so do ever-tightening emissions and mileage standards. Some of the GM engineers who helped design various aspects of the LS engine were deeply involved in performance and racing, either in their “off” time or as the result of previous assignments to Chevrolet’s official racing programs.

Read the fascinating facts behind the answer here

Redline Rebuild: Watch this tired big-block 396 go from crusty to trusty – Kyle Smith @Hagerty

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There is no sound quite like a tuned-up big-block. Sadly, when our 1969 Chevrolet Camaro SS396 rolled in the shop it had more of a wheeze than a growl. This engine got a refresh just five years ago, but in that time the car’s duties included teaching hundreds of young drivers how to use a manual transmission, driving road trips, tours, and general use. Given the oil in the ‘Maro’s tailpipes, Hagerty’s Davin Reckow knew there was something wrong but wasn’t sure just how far he’d have to dig to figure things out.

The diagnosis once we got the orange big-block on the engine stand wasn’t good—Hammered valve stems and leaking piston rings meant we had one choice—a Redline Rebuild.

Read the rest of the story here