Big Block vs LS - Chevelle Tech
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post #1 of 250 (permalink) Old Jan 1st, 17, 4:41 AM Thread Starter
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Big Block vs LS

I've already posted about this awhile back however I cant figure out for the life of me how to find the original post (sorry Im a noob). I have a 71' chevelle and im trying to decide between a big block or an ls/lt. The car currently has a bone stock 2 barrel 350. Ive narrowed it down between a 540 using a dart block and an ls7/lsx454 or lt4. The car will be driven a few times a week depending on the weather and is not seeing the track or strip. The power goal is around 600hp/tq as long as its streetable. Id like to keep the build n/a but im not opposed to boost. My budget for the engine and tranny would probably be around 15k though i wouldnt mind throwing a couple of more to get exactly what i want. I pretty much want a mean sounding, overpowered cruiser. Please let me know what you guys think and happy new years.

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post #2 of 250 (permalink) Old Jan 1st, 17, 5:36 AM
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Re: Big Block vs LS

Big block, Mike Lewis...


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post #3 of 250 (permalink) Old Jan 1st, 17, 5:45 AM
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Re: Big Block vs LS

To each his own, but when I walk up to a chevelle with the hood up, I want to see a big block.

LS is an excellent platform, and has it's place. So do nice, big ol' fat blocks!!

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post #4 of 250 (permalink) Old Jan 1st, 17, 9:04 AM
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Re: Big Block vs LS

BBC, only way I would do the LS is with one or two hair dryers. JMO.

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post #5 of 250 (permalink) Old Jan 1st, 17, 9:19 AM
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Re: Big Block vs LS

Well I have a 540 and a 454 LS7 style motor and both perform great The 540 is in a 1965 Chevelle and the 454LS is in a 2006 Corvette. I would say I have to agree with the guys above open the hood a big block Chevy is a nice thing to see especially a 540. It just fills the engine compartment so nicely. The LS is a great motor and puts out a lot of power and is about 200 pounds lighter (a fully dressed one is like 440 pounds). The big block is a direct fit no custom anything or computer stuff which is nice. The 540 will put out lots of power and 600 hp is actually a low number for that motor you could do 650-675 flywheel hp and still seem mild assuming you go hydraulic roller and good heads etc. And one thing the 540 has is torque. Stick with a standard height deck on the 540 so everything just bolts in and hood clearance is easier get a cowl hood. An LS can also do 600 hp my Corvette actually does 610 hp and 565 tq and that IS AT THE TIRE (not flywheel). So I would say go 540. A recommendation is chassis dyno whatever you get for a final tune.
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post #6 of 250 (permalink) Old Jan 1st, 17, 9:20 AM
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Re: Big Block vs LS

Very Good Question ! I have a one owner LS-5--M-22 1970 El Camino and a 1970 Nomad Wagon,,, Driver with a 468 & a 700R4. I also have a 010 1/2 ton X Cab. Silverado with a 6.2 ( 413 H.P.) & a 6 speed and the 14 bolt rear.
I am a Geeser and I LOVE the look of a big block between the fenders. That being said, I raced a 427 COPO at the track, YES I lost the race with my 1/2 ton 4WD truck ( By a Truck Fender).
When I mash down on my Silverado with the A/C on, It shifts at 5800 RPMs. and runs on 87 Octane.
To unleash the beast in my truck and go fast shut off the " Traction Control " and use the " Tow Haul Mode ". Then it will kick both of my B.B. Chevys AZZ.
Again I say, NOTHING looks better in a 64-72 Chevelle than a big block ! If I ever do an LS Engine it will be in a 4 door built to go and not look pretty. YEP, My LS project would be a 100% beat up 64-72 Chevelle of some sort, With 40-50 years of patina and not pretty BUT have a go fast driveline.
I love driving my 468 Wagon, With a Q-Jet it always does around 20 MPG. I drive it around 3-4000 miles a year. Many choices with Engines. DO what makes you happy. I do believe my 6.2 Silverado 1/2 ton will kick my LS5-M/22s butt any day of the week.
That big " Orange " chunk of iron, Sure looks BEAUTIFUL in any Chevelle.
P.S............. Your Car.....Your Call !
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post #7 of 250 (permalink) Old Jan 1st, 17, 10:34 AM
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Re: Big Block vs LS

LS! ! They're the engines which are slowly replacing the small and big block generation. They make way more power with less cubic inches, are computer controlled, run smoother are more economical to operate. I have a big block in my Chevelle because it was already there when I bought the car but if I would have built it myself, without a doubt it would have an LS motor in it. My son is currently having a '69 Chevelle restored and he already decided that it will have an LS engine…


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post #8 of 250 (permalink) Old Jan 1st, 17, 11:42 AM
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Re: Big Block vs LS

Nobody can decide for you what engine to run. I have all 3 options available and keep waffling back and forth after 20 years of big blocks. I'm almost at the point of quick disconnects and changing out in a weekend!

Seriously, nothing is going to beat the seat of the pants torque and engine bay filling capacity of a big block. But they are like dragging and anchor around on your front wheels and they're thirsty too. If you can live with something that gets single digits for fuel mileage they're lots of fun.

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post #9 of 250 (permalink) Old Jan 1st, 17, 11:54 AM
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Re: Big Block vs LS

I knew the LS is a superior engine, lighter, better design etc. But my Chevelle has a Big Block because it's old school and cool. Honestly that's the real reason. There wasn't much difference in price between a used 454 and a junkyard LS swap.
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post #10 of 250 (permalink) Old Jan 1st, 17, 11:55 AM
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Re: Big Block vs LS

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post #11 of 250 (permalink) Old Jan 1st, 17, 12:10 PM
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Re: Big Block vs LS

No doubt the ls can perform strong but to me anything but a big block in a chevelle just doesn't have the same wow factor in the engine bay it just fills it up so nicely and they usually pull HARD

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post #12 of 250 (permalink) Old Jan 1st, 17, 12:12 PM
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Re: Big Block vs LS

Depends what you want out the car, I like a BBC in an old car that isn't driven a just suits the car. If I wanted to tour the car lots I'd consider an LS with OD. I think you're really over building going with a 540 vs a 496, you're going to spend $8k engine, $2k trans, $2k diff and another $2k with bolt ons... Them add in suspension and upgraded brakes, and drag radials. You'll be right on budget!

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post #13 of 250 (permalink) Old Jan 1st, 17, 2:17 PM
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Re: Big Block vs LS

My perspective depends on what the purpose is for the car.
If it is to build a spirited driver, I'd go LS for trouble free operations, good fuel economy and well mannered driveability.
If the purpose is for resto, show, minimal driver or drag racing, nothing makes the impact of a nicely dressed big block between the frame rails. (PS I'm not saying an LS can't be raced.)
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post #14 of 250 (permalink) Old Jan 1st, 17, 4:48 PM
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Re: Big Block vs LS

If you're on the fence, stick with the ancient analog stuff. This discussion can go on forever. What it boils down to is what your comfort level is and how you want to drive the car.

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post #15 of 250 (permalink) Old Jan 1st, 17, 5:06 PM Thread Starter
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Yeah the car isn't going to be on the track or strip , but for sure it will be an overpowered grocery getter & letting it loose on open roads. I'm hooking it to a bullet proof trans and rearend and probably going with qa1 suspension package.
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