Interesting 383 LS vs SBC video

Discussion in 'Engine Topic' started by biker, Jun 5, 2021.

  1. sooner

    sooner Veteran Member Lifetime Gold Member

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    Ha! yeah those speedmaster heads sucked.

    I thought that CNC ported heads were always better than as cast heads :crazy:. I guess with those heads being CNC ported, they will be bad consistently though..well as long as there is enough material there for a cleanup with the tool.
     
  2. ULTM8Z

    ULTM8Z Veteran Member

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    For someone like me who only wants about 450hp, a standard sbc 383 will do the job easily and still give a smooth idle and good street manners.

    I suppose if I wanted the cool factor and the latest and greatest tech, it might be worth it to go LS for when I pop the hood at a car show. But for me, not worth it.
     
  3. biker

    biker Veteran Member

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    Same here. I have nothing against the LS, in fact I love it. As I explained before, it is simply an evolution of the SBC, incorporating improvements much like Harely Davidson did through the early years.
    But, i know how to tune the sbc, it fits in everything I own and I have plenty of parts to last me til I kick the bucket.
    Doesnt mean I wont put an LS in something if I can put the parts together and save a few bucks.
     
  4. jeff swisher

    jeff swisher Veteran Member

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    I looked at the 2 heads used in this test and on paper they flow almost the same numbers
    I do not think the Injection had an advantage over the carb.
    I do think the longer runners on the LS had the advantage.

    .050" duration numbers will not tell the entire story on cams.. that higher lift LS cam may have more area.
    It may even close the intake valve earlier to build more cylinder pressure.

    High air speed will fill a cylinder very well also and this is why a tall Tunnel-ram makes more power.
    I would bet if you just took a dual 4 tall tunnel-ram and stuck it on that old school 383 it would be darn close if not more HP than that LS.
    Not using any 450 carbs either something in the 600+ cfm each area.
    I have ran rams with 450's and 600's and the 600's are worlds better everywhere.
     
  5. badazz81z28

    badazz81z28 Veteran Member

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    You just can’t accurately compare the engines. If it was apples to apples...it would be the same engine. I just get a kick out of the pecker measuring...and the hate or love for LS engines...For what the LS offers and if you take advantage of it, its better than the SBC because its a refined SBC....just like how they keep getting better with LT
     
  6. biker

    biker Veteran Member

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    Exactly. The LS does what any good evolutionary upgrade is supposed to do. Makes more power more efficiently and more reliably. A SBC with good parts, built properly with attention to detail can come very close on all fronts. If built right, it can come close enough to make it a tough choice which is why most people agonize over the choice.
     
  7. badazz81z28

    badazz81z28 Veteran Member

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    That’s what makes this such a debate by the die hard SBC fans...people less forget, one of the major appeals to the early LS swaps, and even so much today...was the ability to pull a modern engine out of 4th Gen Camaro, GTO or Vette and have 300+hp...STOCK! Not to mention the comforts of fuel injection. You didn’t need to do anything to them to have a pretty potent street engine that dominated your typically SBC. Now that people are modifying them more than ever with a growing aftermarket support, 600-1000hp is very achievable with the technology. My LS7, is pretty much a factory engine...makes over 600hp. Are there SBCs that can be “built” to make more power? Absolutely. But the point is...I pulled the engine out of a vette, installed a cam and went. No factory SBC or even BBC engine out of any factory car can do that. Look at the LT4 and LT5....look how easy it is to get a streetable, everyday driver 650-700hp engine....the technology is impressive.

    People need to stop chiming on how much faster their 406 or 383 is than a LS....
     
    Last edited: Jun 7, 2021
  8. ULTM8Z

    ULTM8Z Veteran Member

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    Each one has it's place IMO, for the reasons that biker and badazz mentioned...

    I do agree its silly to try to make comparisons though... I remember back in 1993 when the 4th Gen F-bodies came out and Chevy High Performance ran an article asking the question if the new Camaro LT1 was better than the 1970 Camaro LT1. I was thinking, are you kidding me? Why wouldn't the new LT1 be better? Making essentially the same net hp, but with a smooth idle, good street manners, twice the fuel economy, etc... Are the engineers that inept that after 30 years they can't improve on it?

    But I will say this though... for an engine that's essentially been around since just a few years after freaking World War II and is still going strong in terms of useage and aftermarket support... that's pretty freaking impressive. What was it, 1953 it came out? Almost 70 years ago? Crazy...
     
  9. Lowend

    Lowend Administrator. .a car, a man, a maraca. Staff Member Lifetime Gold Member

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    I'll start off by saying - the guy built a "dumb" LS motor with a small bore and very high piston speed that was handicapped from the get-go. If he'd used an actual LS1/2/3 with a 4"+ bore and the same displacement, this wouldn't have been as close.

    While the LS heads are very important. One can't overstate the importance of the Fuel Injection setup. EFI allows timing to run right up against the ragged edge of detonation, all of the time. One simply can't do that with a conventional distributor.

    Can you build a Gen-1 small block that's competitive horsepower-wise with an LS... of course, you can. If you're willing to give up enough longevity and drivability you can make almost anything do that. There are lots of 600+ WHP 153cid (2.5 liter) Subaru EJ257 4-cyl's running around. They are expensive and don't last very long...
    The G1 motor has a cam that I would call near the limit of streetability. [email protected] is definitely not going to be a car you take the market on a sub-freezing day. The LS will remote start without missing a beat.
     
  10. muscl car

    muscl car Veteran Member Lifetime Gold Member

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    I've always like Gen 1 sbc engines but wouldn't mind building a 427 LSX twin turbo engine . The 427 LSX has become a very popular engine combo in Drag racing with some making well over 2500hp


    Here's a Texas Speed 427LSX making 1300 plus rwhp on a very conservative tune . This car won its class at Midwest Drag week with a best time of 7.64Et / 186mph . It also easily handled the 1k mile road trip between tracks


    Start the video at 10:50 into the video

     
    Last edited: Jun 7, 2021

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