LS3 480 questions ......

[NovaSF]

Hello everyone. Planning a big overhaul of my Nova soon, getting the engine choice settled. Leaning towards a pull out stock LS3 or the LS3 480 and I have a few questions.....


1 - A stock LS3 with headers and a tune seem to put out about 400-430 rwhp according to the all knowing internet. The only dyno #'s I can seem to find on the 480 appear to be the same. Does the 480 with a hotter tune put out more power? Any proof of this?


2 - my current 383 leaves me smelling like I took a bath in gas every time I drive it. Does the LS3 480 smell like a gas station at idle/low speeds/putting around town? Is this based on the tune? Apologies for my ignorance...


Appreciate the help/advice. The car will be a weekend toy for the family and I to cruise around in. Looking for some fun (450-500 hp/tq) but want the reliability as well.

[badazz81z28]

I’m pretty sure the more powerful crate engines are using different cam profiles. You can’t beat a new crate with a warranty, when the warranty runs out...swap the cam.

With a used LS3, you can go aggressive as you want with the cam and high 400s to the tire is not out of the question.

Regarding the fuel smell, you’re gonna get that with the LS too if you don’t run cats.

[65 drop top]

The LS3 480 crate motor actually puts out closer to 495 hp at the crank. With a 15% drivetrain loss, you'd have 420 to the wheels.

[badazz81z28]

^^ depends on how you dyno it. Is it dyno’d with or without accessories? Headers...manifolds.

[rickpaw]

...Regarding the fuel smell, you’re gonna get that with the LS too if you don’t run cats.

Not sure if that's entirely accurate. I had a Pontiac 400 in my Firebird, swapped it out for a bone stock 5.3 LM7 with no change in the exhaust system. The fuel smell is significantly less, and almost non existent at idle.

[Schwartz Performance]

The fuel smell of a carb compared to LS is a big difference. My 406 sbc smells pretty bad idling. However, I like the smell of gasoline, lol.
The hose used makes a difference too, and venting.

The "430" put out 390 rwhp on a car we just did, 1.875" headers, 2.5" exhaust, through a 4L65 and a 9" diff. It was tuned on the dyno.

GM did update their rating on the 480 to 495hp in the last couple years. I'd estimate it'd be 430ish to the tire with same specs as above.

I'd be happy to help you purchase whichever crate engine you end up with, if you don't have anyone picked out yet.

-Dale

[badazz81z28]

Not sure if that's entirely accurate. I had a Pontiac 400 in my Firebird, swapped it out for a bone stock 5.3 LM7 with no change in the exhaust system. The fuel smell is significantly less, and almost non existent at idle.

Very subjective, the cars carb maybe way out of tune and pig rich. I agree a carb car can smell very strong of exhaust and a fuel injected car be less, however I’m on my 3rd LS swap and there’s a exhaust/gas smell. Because 1 there are no cats and 2 the engine is cammed and overlap will give you a exhaust smell. Don’t think you can put a LS in the car with no cats and it will have no smell like your daily driver modern car.

Your gas small can also exist due to the openness to the carb while the LS will be closed.

[icemanrd19]

My ls3 hotcam dynoed at 447 rwhp.

No fuel smell. Car runs great and I wouldn't hesitate to make my car a daily driver if I had too

Where are you located? If you are in Dallas I'll give you a ride

[NovaSF]

Thanks for all the input. I think my 383 is probably tuned like crap.

Iceman, those are good numbers, anything else you can mention about the engine? Low speed surging issues? What tranny are you running?

[icemanrd19]

t56 magnum. No zero issues. Runs perfect out of the box. Ac on or off, hot outside or cold outside it starts up and its reliable.

[icemanrd19]

Thanks for all the input. I think my 383 is probably tuned like crap.

Iceman, those are good numbers, anything else you can mention about the engine? Low speed surging issues? What tranny are you running?

any issues with burning oil from your 383? i have a buddy that has a new crate 383 that burns oil.

[badazz81z28]

My ls3 hotcam dynoed at 447 rwhp.

No fuel smell. Car runs great and I wouldn't hesitate to make my car a daily driver if I had too

Where are you located? If you are in Dallas I'll give you a ride


Are we talking fuel or exhaust?

[NovaSF]

Iceman... yes it does burn a little oil. It's a Blueprint 383 405/440. I can't tell you how much though, it's been in a coma in my garage the pass 2 years

[NovaSF]

Maybe I'll put some high flow cats on the LS3 480 and call it a day. The exhaust smell gets old quick. Going to spend a lot of time in the car with 2 young kids.. Don't want them inhaling it as well

[icemanrd19]

Where do you live?

[NovaSF]

San Francisco

[Btamayo23]

Is your exhaust dumped say before the axle? Or is it routed all the way out to the back of the car? In my opinion that makes a big difference as well. As far as the smell goes.

[another69]

I bought a LS3/480 from Dale at SP, and really happy with it so far. I used to have a carbed 406 that used to make me smell like fuel & exhaust when I drove it. Garage stunk like fuel when I parked it.

Fuel smell went away when I switched to Teflon B&M fuel lines.

Exhaust smell got much better after swapping to the LS3 & making sure that all openings in the firewall & undercar were fully sealed.

Fuel & exhaust smell is now a non issue while driving or parked.