Big power N/A LS engine discussion

[prairiehotrodder]

Did you see the latest car craft with the 8 second SBC malibu ? I was impressed. It was a 434 on methanol and it looked like a really light car. It got me to thinking, why don't i see any N/A LS powered drag cars at the track ? Have they not caught on with the real drag racers yet ? Or are they not the way to go ? Is 750 hp achievable ? I know any SBC in that power range seems to need an aftermarket block and very big cam / heads / compression. With an LS could a guy use a stock 6.0L block and L92 heads ? Save a ton of money right there. Then put in the big cam / CR and run it on methanol ? Spend the money on a good rotating assembly to get the cubes and compression. Put a carb on it.
Every LS i see has is either a fairly tame EFI late model car or a turbo deal that never does the same thing twice when it goes down the track. I'm talking about a fast, reliable, bracket car motor in this thread.

I guess the question i'm trying to ask is, If you were starting from scratch and needed 750 hp NA would a SBC or a LS be a cheaper, smarter way to go ?

Brian

[CGT]

viewtopic.php?f=1&t=51466&p=821736&hili ... ed#p821736

I've been playing with this. I think whether its cheaper or not would depend on what you had to start with, if you had a good core, bla bla bla.

If you had a good useable LS core and didn't have any ancillary parts that you were trying to use from a different engine platform, yeah I can see it being a decent choice.

If you have a good 6.0 or 6.2 aluminum block core like I did or could get on cheap then I why not....knock a hundred pounds or so off the front of your race car while your at it, easier to work on, seal up easier and nicer.


There are pro's and con's with the LS for sure. 750HP is a gray area to me if I had to choose which way to go.

[bullheaded]

I think bracket racers are slow to move to LS power because of a number of reasons. Most bracket racers are generally of the pre LS era,they know SBC's and some have a stock pile of parts for spares. I think the fact that you have to use adapter parts to run a distributor plays into it as well. Then comes the point of how many 750hp SBC's do you see in bracket racing anyway. Most guys who want that power level will just build a relatively conservative BBC and be done. It's fairly easy and cheap (comparatively)to build an 800hp stock block 496 that is good for hundreds of passes.

[LoganD]

Why would you waste your time checking valve lash and replacing valve springs when you can just put a turbo on a 5.3 and make 800 hp reliably? Turbos and EFI have killed the naturally aspirated engine if you want to go really fast.

[prairiehotrodder]

Lets stick to the NA discussion

IMO power adders detract from consistency in a bracket car. I'm sure some will argue.

Do the rectangle port L92 heads flow as good as most high dollar SBC race heads ? Or am i wrong on that ?
As far as ignition, skip the distributor and run the coils with a box.

We all know the stock block can handle huge power. Don't need aftermarket unless its for the cubes.

I'm all about BBC believe me. But knocking a few hundred pounds off the front would be nice. I have a 850 hp malibu just like the one in the car craft article and he is 3/4 of a second faster even though i'm probably making 80 - 100 more hp.

Brian

[Orr89rocz]

They exist. Just most guys go turbo cuz its so cheap and works to well

Stock ls3 heads and intake will make 600-650 hp na on the right motor, by 6000 rpm. Throw a good intake on it and cam to match, 700+ easily done

Ls7 stuff has made 600-700 at the tire in vettes na with hyd roller cams

At the 400+ inch range, it probably cost as much as sbc to do big na power, and perhaps you can say more options exist for sbc for heads and intake choices. I’m not sure

Idk if hes on here or not but matt walter is goin on drag week with a 427 ls thats already been 9.3’s with a stick shift. Thats pretty awesome

[LoganD]

They exist. Just most guys go turbo cuz its so cheap and works to well

Stock ls3 heads and intake will make 600-650 hp na on the right motor, by 6000 rpm. Throw a good intake on it and cam to match, 700+ easily done

Ls7 stuff has made 600-700 at the tire in vettes na with hyd roller cams

At the 400+ inch range, it probably cost as much as sbc to do big na power, and perhaps you can say more options exist for sbc for heads and intake choices. I’m not sure

Idk if hes on here or not but matt walter is goin on drag week with a 427 ls thats already been 9.3’s with a stick shift. Thats pretty awesome

I'm sure there's people going deep 8's NA with an LS. There's NA Coyote's going 8's and even the Coyote stock cars are in the 9s.

[Orr89rocz]

They exist. Just most guys go turbo cuz its so cheap and works to well

Stock ls3 heads and intake will make 600-650 hp na on the right motor, by 6000 rpm. Throw a good intake on it and cam to match, 700+ easily done

Ls7 stuff has made 600-700 at the tire in vettes na with hyd roller cams

At the 400+ inch range, it probably cost as much as sbc to do big na power, and perhaps you can say more options exist for sbc for heads and intake choices. I’m not sure

Idk if hes on here or not but matt walter is goin on drag week with a 427 ls thats already been 9.3’s with a stick shift. Thats pretty awesome

I'm sure there's people going deep 8's NA with an LS. There's NA Coyote's going 8's and even the Coyote stock cars are in the 9s.

Oh for certain there are. Theres 1000 hp na ls builds out there.

[midnightbluS10]

Bob Book uses the LS architecture to build 10k rpm 1200hp NA 400ci pro stock engines. If that's not showcasing their potential, I don't know what is. Tommy at KPE was working on one with Greg Hogue, also, I thought.





Go look at ANDRA Pro Stock racing.

[prairiehotrodder]

can anyone tell me how the L92 head compares to a typical SBC head ? Say a AFR220 ? I've played with 2 LS engines and both were the LY6 version which are relatively cheap and easy to find and come with the big rectangle ports.

[Steve.k]

The LS engine in my view took off because of ease of turbo charging and the return on dollar. The n/a side is quite different and while it may also be hp rewarding not many do it as its not a direct shoe into chassis, where the sbc is! In our area racers are watching dollars alot closer and switching to setups that are cheaper not only to build but operate. Less disposable income here. The ls may not fall into that category like the tried and true sbc.

[Orr89rocz]

can anyone tell me how the L92 head compares to a typical SBC head ? Say a AFR220 ? I've played with 2 LS engines and both were the LY6 version which are relatively cheap and easy to find and come with the big rectangle ports.

From what i read the csa is near 3.2 at the opening and 2.7 at the venturi in the ls3/l92 heads. Thats much bigger than the afr 220 and maybe closer to something like the 245. Valve is larger and flow is similar to the afr 235-245 stuff

It is said the port shape produces a more homogeneous velocity profile and this helps meet cylinder filling and emission requirements of the late model engines

[prairiehotrodder]

Wow, that seems like a huge benefit. Save $2000 on heads right there.

[GARY C]

Bob Book uses the LS architecture to build 10k rpm 1200hp NA 400ci pro stock engines. If that's not showcasing their potential, I don't know what is. Tommy at KPE was working on one with Greg Hogue, also, I thought.





Go look at ANDRA Pro Stock racing.

My guess is that head would be very different in all design points, the counter argument to the LS being better than the other traditional platforms is that the traditional platforms with the right head and combo makes the same power in that class.

The production LS head architecture is the problem with high power NA engines just like the traditional production design.

[Orr89rocz]

Right. Ls7 aside, the main na advantage to lsx stuff is the factory heads whether square port or cathedral are very good, good enough for most 500-650 hp street or milder race stuff. Port stock cathedral heads go really well. Ls3 minor work does fantastic. Not having to buy heads is a big plus vs sbc

But that 700-900 na range, both need work and even out in dollars imo