BBC 427 or LSX LS7....

[Yenko boy]

Having a hard time deciding on a engine for my car which is a 69 camaro. Im bascially deciding between a LSX LS7 crate or building a all aluminum 427 big block. Now I have all of the parts for the 427 Big block minus the 4 thousand dollar aluminum block but all of the parts are brand spanking new. Which makes me lean a little more toward the big block. Im looking for a good street/strip high fun factor motor. Any oppinions?

[danbob67]

you cant go wrong with a big block wish I had one. plus you got most of the parts already, go big.

[class67]

For street/strip, you can't go wrong with the BB but for handling purposes, I would lean towards the LS7...IMO

[Project69]

Big block FTW!!!!!!! lol

An all aluminum BB would wax the floor against an LSX

[formula]

depends on what kind of floor you're waxing.

The big advantage to the ls7 would be that you could, at least theoretically, get the CG down low thanks to the dry sump. that plus sweet oil control and a crazy redline, plus a little less poundage, makes it a better choice for the track/handling.

For the street...an all aluminum 427bb will be a torque monster. Torque is way more fun on the street. You've already got everything but the block.....I say your decision's pretty clear, even though I love lsx's to death.

edit: researched engine weights a little bit...from what I read, an all aluminum 427 should weigh around 585 lbs, a traditional small block weighs around 575 lbs, and an ls7 is 458 lbs. So there is certainly an advantage to the ls. If that advantage is great enough to warrant selling everything you've got for the BB and starting from scratch is up to you.

[gmjj13]

go with the BBC. is it going to be EFI'd or Carb? either way, it will be way fun on the street, and plenty of fun at the strip.

[Vegas69]

You still can't and never will be able to beat the look of a big block chevy. After all it is a muscle car.

[Project69]

You still can't and never will be able to beat the look of a big block chevy. After all it is a muscle car.

Yup, the look people give when they see the size of those heads :eek:

[Fuelie Fan]

Why does everyone keep saying that the big block will make more torque? If they have same displacement and can accommodate the same cylinder pressures, they should be capable of equivalent torque. Heck, it has 475 ft-lbs STOCK and lingenfelter gets them to a reliable 575. Plus, you'd never have to worry about cold or off-idle stumble with EFI. I understand the look and aura arguments, and they do have validity, but from a performance standpoint, what am I missing?

[PhillipM]

Big block FTW!!!!!!! lol

An all aluminum BB would wax the floor against an LSX

Sounds like you need to get out of you Viper and experience an LS7. And not a stock LS7! God knows that BB won't be stock.

[Project69]

You dont think i drove an LS7 vette? Before i bought the viper i test drove an 06' Z06 and a Ford GT (for the hell of it) and i took the viper because it was more fun to drive then the others.

I think someone hates the snakes haha

[68sixspeed]

Alum big block would be fun, but I'd push the CID a lot higher to make it worth carrying the extra weight over an alum small block. For what it's worth an old school alum small block weighs in at 355lbs. Not sure where the lsx comes in with the dry sump stuff though, it might be close.

[Kenova]

Since you have everything but the block, I would say go with the all aluminum big block (I love the way that sounds). It would probably be cheap enough to increase the displacement, but just how much torque do you really want?
My choice if starting from scratch would be a LS based 427 with a wet sump. Start out with Katech's 4.125 block and you wouldn't have any trouble building big block torque, even with the wet sump oiling system.
A crate LS7 engine would be nice, but I honestly feel you can build (or have built) a LS engine with better power and reliability for the same money. If I'm wrong, I'm sure someone will correct me.

Ken

SCREW IT! Build the "all aluminum big block"!

[Texas Hotrod]

I'm taking a break away from my Camaro project to freshen up one of my other cars. The small block in my Biscayne is getting tired, I've been referring to it as Old Smokey to my friends. After 10 years of boosted duty, it's time for the little 406 to go. I'm a firm believer that to the average onlooker, the engine makes the car (but us here know better).
Peolpe always ask if it's a 350. Their jaws seem to drop even more when they are told it's a 406 (I don't see the big deal). I guess it's big to Mr. Joe Blow, when most engines are 5 liters or less.

https://static1.pt-content.com/images/noimg.gif

I pulled a 4-bolt 454 out of storage and scrounged up a forged crank from a GMC 366 truck engine, which will make it a 427. Shorter stroke than a 454, making for a better RPMing engine and friendlier at freeway speeds. Aluminum heads and rollerized valve train, it'll scoot.
This toy is mainly a cruiser for me. Such a big boat is a hand-full when things get hairy. I myself have never had a big block car, I can't wait to compare the two.
People love the small block, wait 'till they see it with the big one (with the blower).
Go for the BB427, I am.

[Adam's 55 Chevy]

Build an ally 540ci big block and stick 427 decals on it! A BBC fully dressed is a thing of beauty. They may be strong and reliable but modern engines are just fugly.

[MarkM66]

Yeah, if you going to build a BBC, it only makes sense to go to a 540 or so.

[Yenko boy]

Thanks for all of the comments guys. I chose a 427ci BB because of the shorter stroke it will have and the combo I have put togather will let me rip it to 8,000 rpm. Yes I have good internals. The combo I have will make about 650 BHP. Not looking for alot of torque down low I wan't more power up high. I am currently looking at a ls7 for 9 grand but what will the complete conversion cost anybody know?

[PhillipM]

Thanks for all of the comments guys. I chose a 427ci BB because of the shorter stroke it will have and the combo I have put togather will let me rip it to 8,000 rpm. Yes I have good internals. The combo I have will make about 650 BHP. Not looking for alot of torque down low I wan't more power up high. I am currently looking at a ls7 for 9 grand but what will the complete conversion cost anybody know?

I would say depending on how much you do your self you will probably have between 3 and 6k to install the LS7. That is a off the top ball park.

[CRead01]

i am suprised so many people are saying a big block. I have a 454 with an aluminum top end with just under 600 horse and a friend has a ls2 that is lightly built up. while mine has more power I feel like his car is a little more fun on the street. I have been thinking about switching to a lsx motor for a little while now.

[1969CamaroRS]

Don't stop at 427, go 498 on a Big Block, pretty popular size now a days on a BBC.

[LS6 Tommy]

Why does everyone keep saying that the big block will make more torque? If they have same displacement and can accommodate the same cylinder pressures, they should be capable of equivalent torque. Heck, it has 475 ft-lbs STOCK and lingenfelter gets them to a reliable 575. Plus, you'd never have to worry about cold or off-idle stumble with EFI. I understand the look and aura arguments, and they do have validity, but from a performance standpoint, what am I missing?

They may have equivalent torque peaks, but they make them at different places on the curve. The LS7 has a bigger stroke and a smaller bore than the Mark IV 427. You can spin the daylights out of a good Mark IV, plus that new ZL1 block has a lot of room to bore. The LS7 may make more torque at a lower rpm for street manners, but GM says 7000 rpm is the max you should turn it. At least a stocker. The Mark IV will really pull on the top. Depending on what cam, heads & bottom end he uses, he can see and easy 8000 rpm. IMO, the Mark IV has more potential in this situation just because I think he may make more power for the same or less money unless he put a power adder on the LS7.

Tommy

[Yenko boy]

I really appreciate all of the help guys. I have decided to keep the BBC 427 and put a big single on it to make it a bit more unique.

[badazz81z28]

I really appreciate all of the help guys. I have decided to keep the BBC 427 and put a big single on it to make it a bit more unique.


So what came of this?

[MAGONSTERZ68]

I’m a fan of big inch LSX power plants just because of the advantage of newer tech and design.