Crispin

I need a LS-engine for registration with a MAX of 300 bhp and 385 Nm (284 lbs/feet).

I've been looking at the 4.8l Vortec engine but it seems even that engine has a tad too much torque.

Any ideas!?!

Isolde

iTrader: (4)

Why only 284 ft-lbs? The '99 4.8 was 285, isn't that close enough? The '00-'04 pickup 4.8 was also 285 ft-lbs, but was up to 270 hp, from 255 in '99.
There's nothing in U.S. registration law that specifies engine torque, and transmission torque ratings aren't that absolute. Plus if you live at higher elevation, you're not getting all that the rating suggests, anyway.

bronx_peanut

Just take your 4.8 and slap on some 6.0 heads to lower the compression. Should lose lots of power that way. Good luck.

Crispin

Thanks for the info, it's not for a registration in the US.
They go by the factory rating so a dyno or a custom engine is not an option.

285 ft/lbs might be good enough, what specific make and models have that engine?

Thanks!

bczee

iTrader: (12)

The 4.8L was 1st produced in 1999-2007 for the Gen III and can be found in many GM/Chevy Trucks, Van's and SUV's (I would say it wasn't the most popular option to order, 5.3L's are more common). Also as a Gen IV engine from 2005 to present. So.. there should be a lot of them out there in the junk yards or intenet ordered (eBay or Craigslist).

I think I read that the Gen IV is near the end of life and that the Gen V will start being used in the next few years.

BTW - where are you located at ? just wondering about those restrictions and why ?

Pop N Wood

iTrader: (1)

My guess is Australia. Have seen similar posts with similar problems.

Clyde65

If you go with a van 4.8 it will have lower ratings.

Jim85IROC

iTrader: (6)

4.8 block + bore to 3.90" + stroker crank + good heads = close enough to legal.

1994t/a

Not to hijack the thread but me and a friend was sitting around drinking beer one night talking about the old 302DZ engines in the 69 z/28s....anyone think it could be possible to put a 5.3 crank in a 4.8 or put a 4.8 crank in a 5.3 and make a LS302 or whatever the cubes would be?Throw some L92 heads on it and a healthy cam.It would be a screaming RPM beast!

NemeSS

iTrader: (127)

i think your buddy has had a few too many
the 4.8/5.3 share same engine block. different crank and rods. same compression height piston.
a 4.8 bored .06 with stock crank would make 303ci or 5.0

even drunk on crown, to me l92 heads on 3.84 bore would be a very bad idea

bczee

iTrader: (12)

Problem. L92 is used for 4" or larger bore engines.. would not work well on a 4.8l or 5.3l engine (3.90") block wtihout problems of the valve being to close to the cylinder/block.

Also. the Gen III/IV engine were built more in mine for long stroke and torque engine.. the old short stroke DZ / 302 engine was a 4" bore/3" stroke and was desgined for high winding applications. If you wanted to do that, I would recommend starting with a 6.0L block and get a de-stroked crank (3").. a 302 is not always a 302...

Pop N Wood

iTrader: (1)

There was a car magazine that did pretty much what you said, built a 302 from an LS motor and stuck it in a 69 camaro. They had a pretty big write up on the motor. I only remember it because they spent a lot on machining and lost a ton of torque and HP in the process.

Saw an original DZ302 with the cross ram dual 4 barrels at a car show in York PA over the weekend. The plaque said less than 40 are known to exist. Pretty rare. Hated to see it in a show car, something like that is made to be flogged.

1994t/a

Thats pretty cool...Id like to have saw the write up on it.We was just sitting around in the garage talking about it and thought it would be a cool idea if someone had the money to spend and do it.Yeah I have only saw one DZ302 car myslef at a local car show we have every year.Its a fairly large show,had almost 900 cars last year.

pushrod36

Back to the original topic: what rating system? I can't recall what year exactly, but SAE changed the way they rate engine output sometime around 2004. I think that most of GM's engines actually ended up scoring higher numbers, but it's something to consider.

Isolde

iTrader: (4)

The SUV versions were rated at 290 ft-lbs. I can't find the van ratings. Mostly look in the '01-up pickups. Also, if you're wanting a manual transmission, only the pickups ever got one, not the vans or SUVs. M/T versions will have the flywheel you would need, as well as an appropriate computer and wiring harness.
If you can't find anything locally, and are willing to have one shipped from the U.S.A., try www.lkqcorp.com.
Once you get it installed and running and legal, then you can do cams and stuff to get more power, since they don't go by a dyno.

loki993

Interesting, but a swap is OK apparently?