FRSTR90

Hey guys,
would like your opinions here... What you would go with... LSX454 or all aluminum 540"? It seems that price would be about the same for both..

My dad is currently doing a frame off on his old '73, he's to the point where he needs to make a decision pretty soon. He was originally planning on going with a cast iron aluminum head 540" until I bought an LS3 camaro over a year ago. I have the feeling that I've been pushing or convincing him to go the LSX454 route.

The plan with this car is to make it into a restomod. He loves style of the '73 and wants to keep the design of the car pretty much stock with minor changes such as wheels/tires and possibly the seats. The car will not be a garage queen, he plans to drive the car regularly when it is nice out. As a matter of fact, his dream is to drive the car across the country.

If he goes the 540 route, he will shoot for 750+ HP. On top, he would put the FAST EZ EFI w/ the dual quad set-up.

If he decides on the LSX454, he would just go with the FAST 102mm intake w/ their computer and etc. We have talked about upgrading the cam in hopes to reach close to 700HP, but we feel that by doing so we would significantly reduce its street ability. From the videos on youtube, it seems as if the LSX454 lays down about the same amount HP to wheels as a stock ZR1. So, with that said, he may decide to leave the engine stock.

Either engine will be mounted with a T56 Magnum or 4L80E. I've been pushing him hard to go with the T56... So, we will see. The rear-end we believe is a 3.70, but we haven't measured. If not, it is a 3.55, but they may change down the road.

Your thoughts and opinions would greatly be appreciated!

427Hotrod

Well...both will be a heck of a lot of fun!

The LS stuff is amazing...but it just like any other engine..it comes down to the heads. LSX stuff is good and it doesn't take crazy cams etc to make good power.

A 750 HP 540 is going to be incredibly easy to do with a decent hyd roller cam..and the TQ will be insane. I did a HR 555 a few years ago with just bolt together stuff...nothing fancy. It made 760HP with a very streatable HR and an HP 1000 Holley. Same cam went 800HP with a Dominator and bigger intake. Well over 700 lb ft also. Made 850 HP with a solid roller. I even tested a solid flat tappet that also made 760'ish with the HP 1000 carb and 820'ish with a Dominator and big intake.

My 555" made 871 HP with a very streetable SR cam.

So it just depends on what he likes. The 540 can be built with good forged parts and be super reliable.

Which *look* does he like?

JIM

MrForce

Crate LSX454, call Comp for a cam, add the 102/102 setup, and a set of long tubes, and your at 650 FWHP.

ajrothm

All Aluminum 540.... A 540 can make 750hp with a plug wire off... 4l80e and a good converter... Mid 9 sec car and daily driveable... Whats not to love?

Do some research on those LSx454... They make some solid power with the right cam (ie. not the cam it comes with) but they definitely have some issues..

Not to mention an all aluminum 540 would be considerably lighter then a LSx454..

Nothing looks better then a big block under the hood of a C3..

JoeC427

Amen brother!

TheSkunkWorks

With that much projected power in either case, has available traction been considered? Just bringing this up because while being power rather than traction limited certainly sucks, excessive wheel spin doesn't do anything positive for actual performance, especially if your definition of spirited driving includes more than burnouts and straightline acceleration (nothing against drag racing). Aborted doing a 496 in favor of another 427 over this very concern. My $.02, but YMMV.

qwank

Aluminum 540 BBC

I'm sooooo over these LS swaps. it was cool 10 years ago. Now everyone is doing them.

l88rocket

I haved both combos, the lsx will make the bbc will and maybe slightly cheaper, but there is nothing like bbc hp and sound. I did Lsx 454 with the raised port Dr heads and made 800hp. Guess it comes to what you prefer

63mako

http://www.ultrastreet.net/engines/5...treet_lite.php
Don't think you can build it for this.

3JsVette

Texas69

Building a 540 isn't exactly breaking new ground either....

Can't lose either way...the 540 would be the least hassle of the two to build and especially install.

qwank

I'm just saying I'd rather see a traditional looking engine under the hood of an older car.

cv67

Yep....remember the TPI then the LT1 swap craze. Cant give away a car with those now. LSx..maybe slightly different story.

Sure they are great motors but with a C3 Id want to keep some kind of traditional flavor so Id opt for the 540. Plus its all aluminum? sorry thats engine **** right there!!

You just expect to see a huge BBC when you pop the hood on some of these old cars.

garygnu

thats a great deal for a alum 540.what rear diff is going in this vette?the ls engine should get better gas mileage .whats your budget for tires ?

SHAKERATTLEROLL

Was this a Trick Question lol.

I will change this up a little Bit as all this really depends on how old the person is that you ask. If they are say in the Mid to late 40's they will most likely say Big Block. While younger people like this new stuff coming out and say LSX or something to that effect. And there are those that just wish to have something different.

I looked at these options as originally I was thinking handling and MPG. But in the end after self examination along with any information I could find the MPG was pretty much of a Wash as in the difference in about MPG did not make much difference to me at least.

Plus you also have to remember that as you go up above I would say 550 to 600HP then you really have to start watching your differential components and start upgrading. But you can head some of this off by using tires that are not sticky and will slip before something breaks. And being careful with your right foot lol.

But since I am 50 lol. I feel that there is nothing that sounds like a GROUND POUNDING BIG BLOCK.

Ever Hear a Good Big Block through Headers at 8000 RPM or so. That my Friend is Music. And it will make Moms run for there kids to bring them back in the house lol. Awwwwwwwwwww The Good Old Days when Gas was $O.45 a Gallon for Premium with 104 Octane lol.

ajrothm

That's a pretty good price for an all aluminum 540, and pretty good hardware in it as well, but the HP/TQ that thing makes is pitiful... If I spent $14k on an engine and it didn't make 800hp, I'd throw up on myself...

My 496 made more power then that al 540 at literally half of the cost..

But that 540 does have some great potential with a few minor changes.

Man an aluminum 540 would be the $hit...

cv67

Good platform! Probably built it to be beat on and not hurt itself kind of an idiot proof crate if theres such a thing.

TimberwolfFXDL

Is 750hp even practical to drive? One of the magazines did a 600+hp build in a 1st gen f-body. They said it was almost useless on the street, and became more of an annoyance to drive than one would have though. Traction was non existent. You couldn't push the pedal through a nice sweeping curvy roadway.

I think it sounds like a lot of fun in theory, but without a hell of a lot of chassis and traction mods (read as: "NOT a restoration job") it's going to be a car show queen in the end

cv67

True...you get in the 500hp range traction is an issue period.

Unless youre into 80mph roll ons its a waste. Have no desire to be breaking tires loose at that speed. Looks neat but I wouldnt want to be in the car when it starts skating or hunting for an exit that isnt there.

gdh

That's been my concern about doing an lx swap, even though I have no plans for selling I just have doubts that I would drive my vert enough to gain all the benefits out of the swap. I might crate the original engine and drop in Gen1 crate at some point just to keep looks consistent.