Ls3

[RdHuggr68]

I am looking at 2 different LS3's from GMPP one is LS3376/480 part #19258768 the other is LS/376/525hp part# 19259233. These engines are pretty much identical other than cam specs that are pretty close to the same specs.
Why is there so much difference in horsepower?

[RPitts]

I bought the 525hp and i believe the cam makes that much difference. Crazy stuff!

[Motime]

I have the 480. The 525 wasn't available when I bought it about 18 months ago. I'm very happy with mine, but I would buy the 525.

[rustbucket69]

I've read on other forums that the LS376/525 is not very streetable and runs "rough" at best. However, I have not seen an actual motor running (that I know of) and many other posters on the thread indicated they have the motor, but haven't finished/fired their cars yet.

I too have looked at the various LS3 variants trying to decide what to run. I'd love to see some guys running these engines chime in. Or, is it better to get a bone stock LS3 and upgrade the internals with aftermarket? Better in terms of performance, cost and streetability?

Sorry to hijack your thread...

[youthpastor]

here's a 525 hp LS3 in a customer's car. We have put some miles on it and it is his wife's car and VERY streetable. Rough idle but the factory converter works fine. Makes crazy power. It is a circle track grind that wanted to continue making power past 7K. We didn't feel comfortable spinning it that high

We put a Victor Jr on it with the Mast throttle body adapter so we could run the cowl air cleaner.

did I mention it makes alot of power

[GregWeld]

To answer your original question ---- why with a simple cam change do these engines make different power levels.


#1 is you must compare dyno sheets AT THE SAME RPM level. So the 525hp motor might be making 480 ish at the same exact RPM's but the 525hp motors cam allowed them to spin it 400 more RPM. HP is a mathematical equation of torque (the only thing really measurable) and RPMS play a major role to get there.

The cam (and heads) is controlling air -- motors are nothing more than air pumps... pump more air = make more power. Pump more air at higher RPM's = larger HP number.

[GregWeld]

GM SPECS


LS3 480 engine


Power: 480 HP @ 5750 RPM, 475 ft. lbs. of torque @ 4500 RPM



LS3 525 engine


Power: 525 HP @ 6300 RPM, 489 ft. lbs. of torque @ 4400 RPM

[Tom.A]

I don't have either one of the those LS3 versions but have the stock 430HP LS3 in my chevelle and love it. Makes good power with no drama

[CFster]

Originally Posted by Tom.A

I don't have either one of the those LS3 versions but have the stock 430HP LS3 in my chevelle and love it. Makes good power with no drama

I have that motor as well. 400hp at the wheels on the dyno, so figure around 460-480hp at the crank. Slightly underrated. I wonder if the other versions are underrated as well.