Convince me to build LS instead of BBC!!!
I've been in the same boat for almost a year with what the hell I want to stuff into a car next. I drive people CRAZY around here.
But ya gotta keep asking and driving everyone batty if you want to get what you really want in the end.
I kno exactly what you mean.. I have listed question after question over at chevelles.com and my most recent post about ls vs bbc somehow turned into sbc vs ls and there was no turning back so i decided to give it a shot here and im glad i did..
the 632 sounds so tempting esp with a nitrous shot... but i think the same can be achieved with a adding an i/c to a procharged 540 and dialing the boost to say 15-16 from say 8-10... ahh here come another night of no sleep hah
on a side note.. do you kno if the dart big M or GM Bowtie BB allow you to use a thrust plate to hold in the roller cam instead of a button.. googling didnt give me a clear cut answer
the 632 sounds so tempting esp with a nitrous shot... but i think the same can be achieved with a adding an i/c to a procharged 540 and dialing the boost to say 15-16 from say 8-10... ahh here come another night of no sleep hah
on a side note.. do you kno if the dart big M or GM Bowtie BB allow you to use a thrust plate to hold in the roller cam instead of a button.. googling didnt give me a clear cut answer
Now go there and drive'em nuts like I have many times.
.
ever again, it will be lsx for me or nothing,
but u cant argue the power to price ratio for a built bbc, thers no replacement.
a 502+with a hp holley dp and solid roller will be hard to beat.
i would go with a hi compression, solid roller, killer flowing heads and intake
and a plate even for the street.
for drivetrain i plan on a worked T56 or the Gforce T56.. usual beefed up rear end with axles with a form of trac lock with 3.50 or so gears.
for chassis ill do any kind of weld in or bolt in stiffeners or connectors i can find.. new A-arms and all... for the rear no sure if im gonna stick with the stock geometry or go for a 4 link...
A 427 LSx will WHIP a 427 BBC. The ENGINE is better, and cube for cube, there's no contest. The fact that the BBC can be expanded for more cubes (only a matter of time before the tall-deck LSx takes 'em down, too) doesn't make it better, it makes it bigger. Not saying the BBC isn't a good engine, but there's a reason we're using 6.0s and 6.2s in Trucks now instead of the old 8.1L BBC.
That quote of yours is true, but the LSx is FAR superior to a BBC.
Back on topic, I personally wouldn't want nitrous. Big cubes with or without forced induction will get you what you want, but big cubes and nitrous enough to support means spending as much time filling the bottle as you do squeezing it. I like your procharger idea, I've been struggling with how to have a nice-driving high HP car on the street for a while, and FI with adjustable boost is what I keep coming back to.
Last edited by IFRYRCE; Nov 6, 2007 at 09:36 AM.
I like the procharger idea because the boost built motor will be very mild when off the boost. this way i can actually enjoy it on the street instead of sliding everywhere. two separate tunes?? so what thats what EFI is for..
The Best V8 Stories One Small Block at Time
New performance stuff all the time is being developed for the LSx's, exciting cutting edge stuff: not only on the mechanical side but also electronics. Alot of R&D is going into these engines. In the near future you may be able to have 700rwhp and get 20+ mpg.
Now the drawbacks are expense, but if your considering a swap with a 600+ ci powerplant your expense will probably be equal. You will need upgrades in the front clip, fuel, cooling, tranny, driveshaft, rearend. For a street car that sees occassional strip, an LSx.
Now if you want to pop the hood and have everyone say "wow thats big" then a BBC.
CI is CI it doesn't care what block it is out of. Are there better heads for the BBC, yes, no question. However, a given number of CI will only be able to use a given amount of airflow at a given rpm.
A 427 LSx will WHIP a 427 BBC. The ENGINE is better, and cube for cube, there's no contest. The fact that the BBC can be expanded for more cubes (only a matter of time before the tall-deck LSx takes 'em down, too) doesn't make it better, it makes it bigger. Not saying the BBC isn't a good engine, but there's a reason we're using 6.0s and 6.2s in Trucks now instead of the old 8.1L BBC.
We're talking about an LSx which is basically maxed out at around 447-454ci, and 481ci for the tall decks, compared with what the thread starter is talking about for his '70 Chevelle....a big *** 540ci BBC with a Procharger...or even the 632ci N/A BBC.
Gimmie a break.
And, the point I just made is moot anyway, just for your info....cube-for-cube a BBC 427 will KILL any LSx 427. Its all about the heads and intake, apparently you don't know what BBC heads can do. The LS7 heads are total GARBAGE compared to the heads available for BBC.
Good luck even hanging close to a BBC 427 with any LSx 427.
.
1000 hp out of a BBC would probably cost as much or more than 1000 hp out of an LS so that point is pretty much moot.
1000 hp BB chev is going to be a pavement pounding white knuckle hella car ( not that this is bad if this is what you want )
My tuners car is a 347 cube LS with an F1C procharger that put down 930 rwhp. The thing is completely civilized and hauls *** like nobody's business. Thats a lil 347....
Start with a 427 LS and see what happens.
When I think back of how many times I was into that BBC to set my valve lash... The dang valve train on BBC's suck *** to put it mildy this is where all the problems with them are ( or at least begin )
For a restoration or a pure intimidator street machine I can see the appeal of a big block. For worry free performance and pure speed fun I cant for this its LS power allllllllll the way
And gearhead are you trying to convince us or yourself what way is better? You seem stuck on the 540 procharged, Go with it. It will work either way you'll be happy.
Last edited by PICNIC_GEORGE; Nov 6, 2007 at 01:32 PM. Reason: ADDING TO PREVIOUS POST.
I believe that my wet sump LS7 complete weighs about the same or even a little less than an iron big block complete short-block assembly.

But if you want a monster (500+ cid) drag engine or just love giving your money to ARAMCO or Exxon-Mobil, go with the big block.
.
They already are. stock vs stock LS series is on another level.
Aftermarket is catching up rather quickly, i belive you can do what a 455 with an MID LSX.
Lets really talk about head design. valve angle , cost , weight, ect, ect.
How much is an EFI set-up for an BBC?
Injectors will be the same price, ECM same, intakes ?, exhaust?.....
Parts for parts everything is close depending on the block you want to use.
and yes a LS7 is better than a BBC 427.
here is a link to check out a sample of pricing complete with Fuel injection ( big block)http://www.sdparts.com/catalog/crate...RamJetEng.aspx
an LS7 is what 11k complete, most of these BBC are long blocks rated at 502hp, and how close in price are they with out dated tech.
Yes you can get more CI with a tall deck BB, yes there is much more aftermarket support of a BBC, but real world app, LS all the way.
10.5 Dave your what 7 sec car... that very very impressive. a forerunner. i have no doubt you have had your share of set-backs, but things wil only get better. LS will evolve into much much more or a new platform will arise.
just my opinion






