Small Block & Big Block Chevy Specific - sbc vs. LS7

Just curious, don't know much about the sbc.

Is there more power/torque to be had from using, say a 427 sbc in an F-Body over an LS7 engine. All parts being equal.

I would suppose there are better heads for the sbc and intakes like a Beck or Hogan would be used for both.


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Depends on what heads you use. 15 degree heads, SB2.2, etc can all flow enough to make LS7 like numbers. Probably won't get there with 23 degree heads though.

Depends on what heads you use. 15 degree heads, SB2.2, etc can all flow enough to make LS7 like numbers. Probably won't get there with 23 degree heads though.

So, you're saying that a sbc with the best stuff will just match the LS7 flow potential?

So, basically, an LS7 with the best stuff will simply be better?


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So, you're saying that a sbc with the best stuff will just match the LS7 flow potential?

So, basically, an LS7 with the best stuff will simply be better?


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It depends on how wild you are willing to go. SB2.2 stuff can flow well over 400cfm. On a 427 you can imagine what kind of power that would make. I don't think the ultimate flow potential of the LS7 head has been reached yet, but I've seen them in the 370s.

Keep in mind the camshaft spends most of its time a mid lift, peak numbers are just part of the bigger picture. I would bet money that the LS7 head out powers the SB2 head in the lower to mid flow numbers. Anytime you compare aged technology to new the new is most allways going to come out on top.

It depends on how wild you are willing to go. SB2.2 stuff can flow well over 400cfm. On a 427 you can imagine what kind of power that would make. I don't think the ultimate flow potential of the LS7 head has been reached yet, but I've seen them in the 370s.

A head shop in Lauderdale is getting 392 cfm @.650 lift from his ported LS7 heads.


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Keep in mind the camshaft spends most of its time a mid lift, peak numbers are just part of the bigger picture. I would bet money that the LS7 head out powers the SB2 head in the lower to mid flow numbers. Anytime you compare aged technology to new the new is most allways going to come out on top.

The SB 2.2 Heads arent aged at all. Those are brand new GM heads. They flow amazing to. Some top dragster and circle track guys use those.

Pretty sure they also make 10 degree heads also and the SB2 stuff is really small CC's so helps out with lowend TQ.There are some guys making 650 rwhp with alot less cubes then the ls7......www.ramracing.us.....Check them guys they run all motor and go some pretty crazy #'s.

sb2 heads are wonderful but they are not the top head for a sbc dart and brodix both make canted valve heads that work great htey flow in the 390 cfm range aswell but wont likely work for a street motor

SBC is a better platform if you want to make insane amounts of power for a decent price (try building a ls7)... i know for a fact with as much as the LS7 cost I could build a SBC that would whip the piss out of it all day long....

The ls7 aint god or nothing. You people need to quit acting like it is.

You f orget they still make 18* heads and shit for the SBC... all with new technology in them...

does anyone one of a write up about putting sb2 heads on a iron block

It takes a good bit of money to make them work but they can make some nice#'s.

I agree..For the $13,000 a LS7 crate engine cost i could build a SBC that would lay waste to it. This bandwagon shit is getting old. They both are excellent platforms and both have endless potential. Yes out of the crate the LS7 owns, but it should! it's brand freaking new and more modern. but, once you start modifying shit that all goes out the window. Then the SBC steps up and can hold it's own. I would say the deciding factor would be the ultimate goal for the engine and how deep your pockets are.

BrianEsser,

For your build also consider fuel mileage, low speed driveability, weight and handling.

Makes things a bit harder than just building a motor to top out the LS7 on HP alone.

Dennis

BrianEsser,

For your build also consider fuel mileage, low speed driveability, weight and handling.

Makes things a bit harder than just building a motor to top out the LS7 on HP alone.

Dennis

Exactly! It goes back like I said to intended usage. Do you want a killer street engine or a maxed out race motor. Though the weight thing is negligible with SBC aluminum heads/intake/water pump etc.

Street/Strip car = LSX

All out drag car = SBC/BBC

Im in the middle of a 18* build up checkout this thread for pics and info.

18* SBC build (http://www.ls1tech.com/forums/showthread.php?t=467817)

progress has come to a hault on it due to a new project.I know ,u should always finish what u started. :bang:

Street/Strip car = LSX

All out drag car = SBC/BBC

I'll have to disagree with you there. Maybe once upon a time, yes, the LSX engine family were much better suited for the street/strip... but technology has definitely changed how we look at the SBC generation.

Yes, the LS7 comes with much better heads (and tuning ability) from the factory, and since we're trying to make the comparison fair, why not take a 427 Motown SBC crate engine, throw on a set of Aero heads, top it off with a Holley Stealth Ram (w/it's ECU), and compare them then. Price range should be about the same for both engine's, give or take a few grand... ;)

I'll have to disagree with you there. Maybe once upon a time, yes, the LSX engine family were much better suited for the street/strip... but technology has definitely changed how we look at the SBC generation.

Yes, the LS7 comes with much better heads (and tuning ability) from the factory, and since we're trying to make the comparison fair, why not take a 427 Motown SBC crate engine, throw on a set of Aero heads, top it off with a Holley Stealth Ram (w/it's ECU), and compare them then. Price range should be about the same for both engine's, give or take a few grand... ;)


Couldnt be said any better........

I'll have to disagree with you there. Maybe once upon a time, yes, the LSX engine family were much better suited for the street/strip... but technology has definitely changed how we look at the SBC generation.

Yes, the LS7 comes with much better heads (and tuning ability) from the factory, and since we're trying to make the comparison fair, why not take a 427 Motown SBC crate engine, throw on a set of Aero heads, top it off with a Holley Stealth Ram (w/it's ECU), and compare them then. Price range should be about the same for both engine's, give or take a few grand... ;)

Aren't there sbc heads that flow into the 400's?


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!!! Do you really need that much flow!! its possiblae to have to much head esp on a small block, 400cfm should be expected for well over 500+ci motor. my 496 will only have 325cfm heads, if you go too big you have to turn the piss out of the motor.. i couldnt even imagine on the street. depends on how big of a small block your trying to go i guess. i know you can touch a 454 SB with an aftermarket block. anyway i think 400 is a lil much.. just me though.

Aren't there sbc heads that flow into the 400's?

There have been two valve per cylinder SBC heads known to flow extremely well, in comparison to a four valve per cylinder one. I just tossed in the Aero head concept because the factory LSX heads are potentially that good, and we needed a fair comparison...

Barry Grant introduced a three valve per cylinder head at the SEMA show back in '04. I honestly haven't found the time to research the development on it, but with it supposed to be that cost-effective, it should be able to release the full potential of any SBC configuration, including the forgotten TPI, and pathetic TBI designs...

We shall see though... ;)

!!! Do you really need that much flow!! its possiblae to have to much head esp on a small block

Well, the problem with the LS7 engine is the LS7 intake, it holds the heads back from flowing to their potential. I would never use an LS7 intake. It would be a Hogan/Beck type or the Harrop Hurricane.

So yes, I would think the more flow you have the more power you'll make, given the correct amount of cubes. I started getting parts together for an LS7 build, resleeved block. 4.155 bore x 4.000 stroke...434ci. Or go with a 4.125 stroke....447ci. Either way, as much flow as possible will help.

But I was figuring maybe going with a sbc instead of LSx....IF they can make more power than an LSx engine for a daily driver. Thats why I started the thread. I would have NRE build it.


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