72 Project

Apple vs Apple vs Orange?

Apple 1: 1971 LS5 454 CID has 365 HP @ 4800 RPM, Torque 465 lb-ft @ 3200 RPM (Gross measured at the crank with the engine not pulling any accessories, no air cleaner, open exhaust)

Apple 2: 1972 LS5 454 CID has 270 HP @ 4000 RPM, Torque 390 lb-ft @ 3200 RPM (Net measured at the crank with the engine pulling accessories, air cleaner, muffled exhaust)

Orange: 2010 LS3 376 CID has 430 HP @ 5900 RPM, Torque 424 lb-ft @ 4600 RPM (is this the same net as 1972?)

Thanks

Jim

Shark Racer

More or less, they switched to a tighter certification in the mid-2000s where the tolerances of "net" is much finer. The measurement criteria is the same, but you have a reasonable assurance they didn't test a ringer when it comes to modern engines.

I can't remember the exact details, but the new "net" that GM uses requires that every motor built is within a certain percentage of the rated output.

jb78L-82

Apple 2 and Orange (LS3) are both NET ratings and for the most part derived the same way. The LS3 is probably fairly guaranteed that those are the peak numbers for the 376 @ that RPM. Way back GM and others often could play with numbers on the dyno graph, meaning the 454 did produce 270 @ 4,000 RPM but the question is, did that motor produce higher numbers at a higher RPM, lets say 5,200 RPM?

You can also see how the 1971 gross numbers were way inflated versus the actual HP that motor produced as installed in the car. Unfortunately, Gross HP/TQ numbers are still allowed for any crate motor not actually installed in a production vehicle. If the carte motor has been installed in a production vehicle, the HP quoted will be NET. Example, a crate LS7 427 SB lists the HP has 505 NET, just like in C6Z06. A GM ZZ502 BB crate will list the hp as GROSS 500 HP but that HP is very different from the 505 NET LS7

Lastly, you can see how the SB 376 LS3 will smoke a 71 BB 365 Gross Motor.......