Big Block Chevy or LS1

[Glock 18]

(1) What is the weight difference in a BBC w/aluminum heads / aluminum intake and a LS1?
(2) What modifications are necessary to get 450-500 HP out of the stock LS1?
(3) What is a ballpark figure on these modifications?
(4) And why are so many people going with LS engines these days?

Thanks for any answers. This is exactly what I'm considering doing - LS1/T56 instead of my BBC in my Chevelle. Thanks!

[andrewb70]

(1) What is the weight difference in a BBC w/aluminum heads / aluminum intake and a LS1?
(2) What modifications are necessary to get 450-500 HP out of the stock LS1?
(3) What is a ballpark figure on these modifications?
(4) And why are so many people going with LS engines these days?

Thanks for any answers. This is exactly what I'm considering doing - LS1/T56 instead of my BBC in my Chevelle. Thanks!

1. My GTO dropped 300 pounds going from an aluminum headed/intake 502 to an L92/LS3.
2. The L92 in my GTO has a stock LS3 intake package and a LS7 cam. It makes 418RWHP, which is over 500hp at the crank.
3. A used LS7 cam was 150 bucks and I also installed dual springs and hardened pushrods for reliability. Total cost was about $500.
4. Because they kick a$$...

I drove my GTO to the drag strip and ran 12.50s @113MPH without making any changes and running 200 treadwear tires. I also completed a 4300 mile road trip in my GTO this summer that took me over the continental divide (12,000 feet) and I got 21 mpg.

Andrew

[parsonsj]

(4) And why are so many people going with LS engines these days?

The better question in this day and age is why would anyone ever use a BBC?

[andrewb70]

The better question in this day and age is why would anyone ever use a BBC?

There is a place for big blocks, but certainly not in a pro-touring car with a goal of 500hp...

Andrew

[Randy67]

4. LS engines are the hot ticket now, so you see alot of them going into cars, plus with the original small and big blocks no longer in production cars, they aren't everywhere anymore, the LS engines are. I would bet that in the world of hot rodding, including pro-touring, the old small block is still the most used engine, mainly for its cheap cost.

I would disagree, Big blocks do have a place in pro-touring cars as much as small blocks and LS engines do. Maybe not the ideal engine due to their size and weight, but they are not out of place IMHO.

[parsonsj]

Let's be clear, since my good friend Andrew has muddied the waters.

I didn't say they had no place in PT cars, I asked why anybody would use them today. As of yet, no one has answered that question. As for Glock's questions, Andrew answered them nicely.

The only answer I can think of to my question is that your car already has a BBC, or you got a killer deal on a BBC. Otherwise, I can't think of a single reason why one would put one in their PT car.

edit: Final clarification: note that I've not said anything about a SBC. My so-called analysis is just about BBCs.

[Yelcamino]

Let's be clear, since my good friend Andrew has muddied the waters.

I didn't say they had no place in PT cars, I asked why anybody would use them today. As of yet, no one has answered that question. As for Glock's questions, Andrew answered them nicely.

The only answer I can think of to my question is that your car already has a BBC, or you got a killer deal on a BBC. Otherwise, I can't think of a single reason why one would put one in their PT car.

edit: Final clarification: note that I've not said anything about a SBC. My so-called analysis is just about BBCs.

My reason for choosing to stick with a BBC is because I like them, I'm familiar with them, and they make easy power. Yes they are outdated compared to LS engines, and there's no way in hell a BBC could get comparable MPG. But like I said, I like them - especially when they're spinning at 7000 rpm.

[surnufz]

When Herb gets the aluminum BBC he's been planning, you LS boys better look out!

[Yelcamino]

When Herb gets the aluminum BBC he's been planning, you LS boys better look out!

You tell 'em Bobby! The new block should shave about 130 lbs off the nose!

[Glock 18]

Wow! I didn't expect so many responses so quick. Thanks to everybody, especially Andrew with the spot-on answers! Anybody else want to jump in with your opinion? I especially enjoy reading direct answers to my 4 questions. It really helps to convince me either way about installing a LS engine. Thanks again!

[Randy67]

Let's be clear, since my good friend Andrew has muddied the waters.

I didn't say they had no place in PT cars, I asked why anybody would use them today. As of yet, no one has answered that question. As for Glock's questions, Andrew answered them nicely.

The only answer I can think of to my question is that your car already has a BBC, or you got a killer deal on a BBC. Otherwise, I can't think of a single reason why one would put one in their PT car.

edit: Final clarification: note that I've not said anything about a SBC. My so-called analysis is just about BBCs.

My only point of mentioning the SBC was that while it may seem the LS engines are everywhere, the old SBC is still the most popular engine out there. That will most likely change in the near future.

As for why go with the BBC, Herb and you put out the main reasons: Like them, have one already, got a great deal, or have a lot of the parts for one already. Or maybe you because just want to.

Plus, do we want it to be that in order to have a pro-touring GM car it has to have a LSx engine? Personally I like diversity, seeing different stuff being used. That's just my opinion. No disrespect intended to anyone.

[parsonsj]

Sounds great! I agree about 7000 rpm; that's a magical sound. I try to put my LS7 there as much as possible... it's good for the soul.

[parsonsj]

do we want it to be that in order to have a pro-touring GM car it has to have a LSx engine?

Nobody said that until you did, lol. Of course not. The engine is really a secondary consideration. In general, the pro-touring movement is more about handling and braking than engine choices.

LSx engines, while common here online in PT.com, are still pretty rare in the world at large.

[Yelcamino]

Nobody said that until you did, lol. Of course not. The engine is really a secondary consideration. In general, the pro-touring movement is more about handling and braking than engine choices.

LSx engines, while common here online in PT.com, are still pretty rare in the world at large.

That's for sure! On the rare occasion that we go to the local cruise, all the muscle era cars are still wearing 14 and 15 inch wheels with drum brakes and running the typical SBC with a Holley carb and Moroso chrome/anodized valve covers. People look at my cars like they're from Mars. The only cars with big wheels/brakes and LS engines are the modern GM muscle.

[Yelcamino]

(1) What is the weight difference in a BBC w/aluminum heads / aluminum intake and a LS1?

I found this link with engine weight info. I don't know how old it is, but it helps answer part of your question.

BBC MK IV (all cast iron I assume) 685 lbs
BBC MK IV all aluminum 550 lbs

Now you just need to come up with the weight of a LSx engine.

[Glock 18]

Thanks for the info Herb.

[Vegas69]

Economically, a big block makes no sense today. I still like the look and sound of a big block vs. the lsx. The ease of large cubic inches certainly doesn't hurt either. You can build a 540 in a mild combo and make 700hp. It certainly isn't the easy or economical route. To answer your question JP, that's what we want under our hood! ha ha

[therobski]

Very interesting thread, Not only I'm still old school on my engine choice I'm building an orphan car-64 F-85 post car. I don't want go to the "dark side" with a newer GM motor other than an Olds BB. I'm going to build a 65 425 Starfire motor, all the machining, clearances, built to Olds specs. Goal is 475 HP. pull your shirt off Olds torque 530-550 lbs @ 5,800 RPM. In keeping my stealth look, motor will painted the early 442 motor bronze, may even extrude hone my later W-Z's exhaust manifolds in lieu of headers. I may loose some HP, but with motor build goal I will have plenty to spare. Pictured is my 455 that's in the 67

[analyte]

I guess I'm the odd duck out. My car previously had a BBC in it for the past 9 years.

When I decided to start upgrading the suspension, I also wanted better road manners to utilize my T56 more efficiently so EFI was needed to achieve my goals. Upon reviewing the different options, I quickly came to the opinion that I could buy and install a LSx in my car for the cost of a BBC EFI system. That made the decision easy for me, and I even sold the BBC at a good price to offset the cost of the swap.

Kerry

[G-Rob]

Well this is not as cut and dried as it seems. What are your power goals and your budget? That is the deciding factor right there.

Under about 650hp, I'd say ls motor. But when you're shooting for big numbers, a BBC is the only way to go.

Peoples first objection is the weight. I don't think the weight is a big deal. First, an aluminum headed BBC weighs about the same as an iron headed sbc. Second that weight is mostly in the block, ie down low and mostly behind the front wheels, ie near the cars center of gravity.

I don't see why people get an ls engine and then throw an sc on it. They should just go BBC. The sc and intercooler is heavy, and that weight is carried up high. I bet if you ran the numbers, an sc'ed ls and a aluminum headed BBC would weigh about the same, and the BBC would carry that weight lower, which would potentially mean better handling.

Also, with the sheer size of the bores in a BBC the heads will flow better than any ls will. 400+cfm is pretty common for a BBC head, while 300cfm is about average for an ls head.

So in short, if you are on a budget ls all the way. If you have moderate power goals, ls all the way. But if you want something above and beyond - we're talking 800+ streetable hp, a built BBC is the best way to go. And with a good trans, it'll still return 16 mpg.

Food for thought.