LS compared to BBC

[SuperBuickGuy]

Help me make up my mind on which way to go. MPG would be nice, but I'm willing to ignore that to hear that sweet, sweet music of a BBC.

The nutshell is if I were to buy a 6.0 LS motor and trans from one of the ebay-type sellers - what did it cost to put it in a 72 Chev 2wd pickup? I've done 454s, so that question is more - were you sorry you chose a 454... or vice versa.

[vics stuff]

I have weighed the pros and cons on both. With me I went with the LS motor swap 435 HP is not bad. With a little cam these wake right up. Best of all they are reliable and great on fuel. I can not say that about a BBC motor.
Vic

[Mollzyie]

I like my big block ... Very Loud and nasty . No fuel injection no computer . Don't care about fuel economy I drive truck maybe once a week . Putting down about 450 hp .

[67 chevelle]

I have 2 427s and 2 396s on engine stands ready to go , they have been there for years , after installing my first 6.0 lsx , doubt Ill ever run one again , ls engines are popular for good reasons , fuel economy , is just one benefit , power is what got me , dont get me wrong 396-427 bbc engines have great power , but many drawbacks compared to ls engines , oil leaks topping the list . To buy a fuel injection system for a bbc , you will pay close to what it cost to buy a complete ls engine .

[Mike C]

If you are going to run electronics, IMO you'd be crazy NOT to go with the LS motor. A 6.2 with a 6 speed would be sweet...

But if you don't want the complication (expense!) and aren't daily driving it, big block makes sense.

I pick up my 390hp 427 from the machine shop Friday and once it's put together will be ordering a build TH200 4R. Hoping for 350 RWHP and 14 mpg would make me happy.

[LockDoc]

-
I have had both and I would have to agree with 67 chevelle. After I put the 5.7 LS1/4l60e in the '67 Panel Truck I may never go back. If you do your homework they are really not any harder to install than a 454. My LS1 has some goodies inside which perks it up some. If you want a big block find an 8.1 496ci engine. I have one but I can't decide what I want to put it in. Thinking about the '67 dually. They start all the time, every time, runs smooth and great fuel mileage. Hard combination to beat.....

LockDoc

[davepl]

If stock is a big thing, as it was to me, then a real big block (like my 396) is the way to go.

If driving it is the thing, then an LS powertrain is the way to go. I'm not a big fan of having to live with a lumpy cam, but you can make them sound just as "rumpity rump" as the nastiest big block...

[ptc]

I just cant beleive what I hear about "reliability" from people about BBC engines. These things have been in production for 7 DECADES!!!!! and are still out there on the streets in regular everyday vehicles and RV's....

If that is not reliability then I don't know what day and night is.....

You dont have to build a BBC to the limits to get great power out of them. But if you do they can be very reliable. I have a 700+ HP 496 in a boat and it gets beat to death every season running WIDE OPEN THROTTLE across many lakes and rivers for 6 months at a time. It has lasted 5 seasons so far with as little as an oil change every year. I have checked the lash every year and it hasnt change a .001" in 5 years - So wear and tear is minimal even at extremes. Cant say that about aluminum engines!

And if you have a leaking motor..... thats on the builder!!!! Motors shouldnt leak!!!!

[Tom]

Originally Posted by ptc

Motors shouldnt leak!!!!

HA! Have that convo with a Harley guy. They'll make up all sorts of crap about why its supposed to leak from the factory. Or they just get mad and stare at you.

OP- Combine the two. Buy a 7.0L/427cid LS motor.

[davepl]

As much as I like the old big blocks, I don't think you can compare. After all, a big block passenger car, something mild like our trucks or an Impala, will go 100,000 miles if treated well before needing a rebuild.

For whatever reason, LS motors seem to be able to run to 200,000 miles and beyond. I don't know what the difference is - machining processes, materials, I don't know. GM got it right with these though.

Either motor, done right, will serve you for a long time. And either motor, done wrong, will annoy the heck out of you.

[Ziegelsteinfaust]

Originally Posted by davepl

As much as I like the old big blocks, I don't think you can compare. After all, a big block passenger car, something mild like our trucks or an Impala, will go 100,000 miles if treated well before needing a rebuild.

For whatever reason, LS motors seem to be able to run to 200,000 miles and beyond. I don't know what the difference is - machining processes, materials, I don't know. GM got it right with these though.

Either motor, done right, will serve you for a long time. And either motor, done wrong, will annoy the heck out of you.

The biggest difference in engine life of now vs back in the day is oil pure, and simple. Namely the packet of additives they use now in the synthetic oils.

I had a 325hp estimated 307 I built for a friend who did cell tower installs all over the western US. It lasted 300K miles with very little bearing wear, and very little oil usage. The bores were hammered, but still had life to go. He finally got rid of it because it wasn't going to die when he switched jobs, and wanted to install his 450hp 350 that just sat.

[darrellyates]

Not trying to be a bother, but I want to weigh in.

I will never build another engine with a carb. Fuel injection is the way to go in my opinion, if you're going to drive your vehicle. Starts every time, and with the exception of oil changes, will go 7 years without touching the engine (at that time, it's due for new antifreeze, right guys?). They run great, make very good power and last a long time. Why do they last? First of all, machining tolerances are very good on the newer tooling, and again in my opinion, computers and fuel injection are the best thing that has happened to the internal combustion engine. No more raw gas leaking/flooding the cylinders, and just much faster better adjustments to keep the engine running where it needs to be.

I get the "old school" of having a big block. However, I want to use my truck when/where/how I want, and for me, the LS engine fits the bill better. You can easily/inexpensively buy a 430 or 480 or even 525 HP LS, and for me it was the same money or less than the big blocks. However, it's the "never have to tune/touch" that was the deciding factor for me.

To each his own. Again, I'll never build one that isn't fuel injected (port injected actually). But, then I don't race or require ultimate HP. I'm just getting too old for that.

Thanks for reading/listening to an old man ramble on.

[b454rat]

I agree bout the carb/injection thing. Every vehicle ever owned that was carbed would start no matter how cold, but was kinda a pain to keep running till it warmed up. Any vehicle I had with a big block brought a smile to my face whenever I drove it. Gas mileage was never a major concern, I mean you don't buy a truck for gas mileage, and I never go real far anymore anyways. I personally don't own an LS, but many of my friends do, and they all same the same thing, power isn't that great and neither is the mileage. One has a 6.0 liter, and towed with it, said mileage isn't any better than the vortec 454 and sure as hell didn't pull it any better. So if gonna have crap mileage why not have fun or the power to boot? My plan is kinda best of both worlds, built 8.1 vortec. Big block power with LS electronics and fuel system.....maybe a stroker who knows.....

[CST10]

I like both LS engines and BBC's. But now days everybody's doing the LS swaps. They are nice and all but everybody's got em.

Go to a car show and 9 outta 10 will have one. Kind of bland in looks when they all look the same.

I like to be different. At car shows people will walk right by the LS's and talk to me about my BBC engine almost every time. And if I have ol goldilocks there with the big L6 250 CI engine, everybody comes and talks about when they had that engine.

I say be different but if you go LS I wouldn't blame you. Trouble free and low maintenance is their biggest value.

Yea, I know. I didn't help anything.

[tjc]

what I have seen lately is the guys that put in the ls motor also like to lay their trucks on the ground. Just my 2 cent, but if you can't put anything more than a 100 lbs in the back and you can't hook a trailer to it maybe it not a truck anymore.

[Tom]

Originally Posted by tjc

Just my 2 cent, but if you can't put anything more than a 100 lbs in the back and you can't hook a trailer to it maybe it not a truck anymore.

How that has any relevance to a big block vs LS swap is beyond me.

op- 700hp does not require boost, but yes it requires dollars. Same thing with big blocks though. Remember an LS can go to 454cid.

[mongocanfly]

I agree with Tom...700hp cost $$$$'s no matter if its Ls or bb...and the LS doesn't require a fan to get there...but it may be the simplest way though..it all boils down to which one that you want..when I went LS my hp more than doubled with a stock LS engine and my gas mileage went up 50%..

['63GENIII]

Ive got both at the moment. 2004 Yukon XL with a 6.0 and '63 K10 with the L29 and 5spd. So, kind of an apples and bigger apples comparison for me. The 6.0 had been virtually maintenance free with the exception of external regular wear items (water pump etc.). No internal hard parts but it does weep oil from the timing cover and valley area. 125k on the clock.

The L29 (Vortec 7.4) is relatively new to me (200 miles) and replacing a carbed 396.

While we've used both vehicles for towing, I have always preferred the BB over the LS. Just seems like the LS is always straining a little more than my comfort level can accept. And while the 396 just seemed to lope along no matter what it was pulling, I can tell that the L29 has WAY more torque (and rotating mass) than the 396 could ever hope to produce or for that matter the 6.0.

The L29 does have a cam, injectors and a tune so this may be an unfair comparison. I would really like to see what the 7.4 would be like with a 4L80 in a 2wd truck with a decent suspension.

I really dig this last generation of Big Block and the cool parts that it came with. It does have a roller cam block, fast burn heads, one piece rear main seal and pan gasket, o ring type front timing cover, sequential port injection just to name a few things.

They do make manifolds for the L29 if one really wanted to run a carb but FWIW theres really no point after experiencing an injected Big Block.

Im not sure how many miles were on the engine when I got it but my machinist guessed it was over 150k. It had such low wear on the rotating assembly that I was able to reuse the pistons (please don't flame me, I was near broke at the time and still am LOL), hone the cylinders and polish the crank. All standard bearings and rings. He believed that the lack of wear was from regular maintenance AND the fact that the fuel injection meters fuel so much more efficiently resulting in less carbon in the oil. The heads did get a thorough valve job and that was it.

As far as mileage, the 454 is too new for me to get any numbers. The 6.0 and the 396 were about dead even though. Im fairly certain that the 454 will get lower #s than the 6.0 and 396... especially if I can't learn to keep my foot out of it!

[SuperBuickGuy]

Originally Posted by Tom

How that has any relevance to a big block vs LS swap is beyond me.

op- 700hp does not require boost, but yes it requires dollars. Same thing with big blocks though. Remember an LS can go to 454cid.

a core BBC 4 bolt main is available to me for $500 (actually, $120 if I simply spend the gas to go get one I have a few miles away); the cheapest 6.0 I've seen 2k and the LSx block required for a 454 build (not including the 10k of machining) is $2500.... dollar for dollar I think can build more power with a BBC.

BBC does have rpm limitations because of their valve train, but weight is almost a wash since the 6.0 iron block about the same as a bare bbc 225 for LS, 250 for bbc.

Not just that, but anywhere about 500 hp and head gaskets tend to be the fuses in BBC and LS motors... so as car flippers say, you make your money when you buy the project. What I'm coming up with between the two is I can get a rebuilt 454 for $3000, heads for another $1500 and everything for another $1500 (intake, etc).... with an LS motor, it's about 2k-3k more.

But fuel economy is a thing that factors in this, and in that the LS rules....

I almost like the implied challenge to see if I can make a bbc get high-teens/low 20s and still make the hp number in a C10 pickup... efi and electronic ignition along with smart head choices.... dunno (thinking out loud more then anything else).... so far about the best I've ever got out of a bbc is 13.... that said, my 2006 GTO with the 6 speed got 14 around town at squeaked 17 on the highway...

[BR3W CITY]

Originally Posted by SuperBuickGuy

I almost like the implied challenge to see if I can make a bbc get high-teens/low 20s and still make the hp number in a C10 pickup... efi and electronic ignition along with smart head choices.... dunno (thinking out loud more then anything else).... so far about the best I've ever got out of a bbc is 13....

That challenge can be cheated if your willing to get into the deep cuts of the GM extended vendor parts catalog, and aim the build towards a primary purpose.

My biz partner has designed and built more than 6 variations on the "last" of the BBC's on the 8.1L platform (GM no longer owns the patents on the 8.1, it was sold to a 3rd party and GM buys back what it needs). GM's change to the "modern" ECM/EFI systems during the final life of the 8.1 was a large leap forward in terms of economy.

The needed heads are a big part of the recipe, and are probably the hardest to get. All of the specialty 8.1's and 8.8's (oooh yeaaa) the company has been making use a specially cast & machined head, and intake manifold; different from anything GM offered on any light/medium duty truck.

These can be paired with a very torque focused cam, and will yield a 15-20mpg 8.1 in a 8k pound truck. You'll be redlining around 3600 rpm, but in a tow pig or lifted beast on 38's it would be cool. The designed purpose was commercial duty trucks which don't have access to diesel fuel.

The same platform is used in an 8.8L variety with either a single, twin, or twin compound turbos. The version with small twins (very small for this size engine) can get around 17 on the highway, but is rated in vehicles over 12k pounds. If you've never seen a ******* schoolbus do a burnout off the footbrake, your missing out.

edit: can't use the company name, the contract is private.

[Alex V.]

LS engines are nice and certainly have their benefits over the previous generation of V8's, but boys, I'm not sure what big block you're talking about that isn't reliable and requires a rebuild every 100K. Mine has 122,000 on it and yes, it leaks and needs all the vacuum hoses and valve seals redone, valves adjusted, and the carb. tweaked, but it fires up without protest every time, gets 12 MPG, and pulls several tons without protest. And the Vortec 454 in my BIL's dad's Suburban has 270K on it and, outside of electrical problems, runs like a top, too. In a truck built for cruising, car shows, etc., maybe LS is the ticket, but in any truck built to work, give me the rat.

[mongocanfly]

And here's another...I used to swear I would never ever have one of them new fangled computerized motors..never ever,,,,, welllll after I put 285000 miles on my 99 z71 with only a waterpump replacement I started to look at it different..that engine still had the factory installed sparkplugs..ran like a top,, started everytime..sooooo when the engine in my 81 c30 proved it wasnt up to the task I bit my lip and dropped in a lq9 6.0....I couldn't be more pleased with the results.....now I say never ever will I own a carb motor again...haha...and it don't lay on the ground neither...will haul more than 100lbs in the bed and will pull the crap out of my loaded trailer that weighs 9500lbs loaded..(and I still call it a truck to)haha

[LS short box]

I did LS2 re-sleeved and stroked to 427 cubes. Small cam and L92 heads. It did 480 hp at the wheels on the chassis dyno. That's about 550 hp at the crank. 4L6E trans. Ran great. It was in a 67 Nova. 20 mpg plus on the highway. I wouldn't build anything else.

LS motors come stock with roller rockers, roller lifters, aluminum heads, some have aluminum blocks. All seals are O-rings, No coolant thru the intake. Single serpentine accessory belt. What's not to like?

Just my .02. Everyone should build what they like.

[Eddie H.]

It's just a matter of personal preference, since both are great engines.
Big blocks have been around for more than 50 years and have logged a gazillion miles in all types of applications. There's also a lot to be said for modern technology LS engines. They are powerful, and absolutely dependable, even when working them hard every day. My daily driver/work truck is a 2012, 2500 series Silverado with an LS engine. Loaded with all my tools and equipment it weighs around 9500 pounds, and I have put 100,000 trouble free miles on it in the past 4 years, mostly on unimproved dirt, gravel and muddy roads, in all types of weather. I don't expect I'll need to replace it for at least another 100,000 miles.

[SuperBuickGuy]

what excellent responses, Thank you and keep them coming.

EFI, I play in that pond a lot and wouldn't have anything else on my 4x4s. That said, my latest one has been a nightmare - but mostly because I forgot the magic rule about used EFIs.... if someone is selling it, it's because they couldn't make it work. I will win through bitter determination and an inability to let electronics win... that said, someone could make a solid case for carbs with what I went through with it. I still like EFI because it's so simple - each part does its task, as opposed to a carb where there's use of all circuits in pretty much all conditions.

Carbs - I live in Seattle, it never gets so cold that it won't start or so hot that vapor lock is an issue to consider. In their defense, unless it's a race car - there is zero excuse why it shouldn't start and run with the touch of a key on the coldest morning. Cut the choke body off? well sure, you'll have troubles with your race car. I'll also say that if you can tune a carb, EFI is easy.

I must admit being swayed towards BBC by the 700 hp point - 700 hp in an LS requires blowers and cubic dollars. That said, plug and play to where my wife could drive it is a strong argument for the LS.... that said, I'm not certain I want to kill her with 700 hp - she did fine with 400 hp in my 6 speed GTO. None of you are making this easy, but you all have very compelling points. thank you again.