VAformula

iTrader: (8)

Just wondering what you all would do if you swapped a LTX out. Would you rather swap to a LS block or go with the big block Chevy engines?

Just a random question, thinking of buying another F-body and going big block someday. Wanted to see what was more fun, serious LSX or serious big block build

96capricemgr

iTrader: (1)

are you looking to build a drag car, a street/strip car, an autocrosser, road racer, standing mile car, garage queen, ridiculous joke that never runs again?

Honestly the only thing I would consider a BBC for would be a dedicated drag car and probably not even for that.

SS RRR

iTrader: (2)

There are write ups that entail what's involved in a BBC swap. Do a search.

VAformula

iTrader: (8)

I've read how to do it, and I understand how. I'm just asking which one y'all would rather do to a drag car. I'm not doing this right now so please don't lecture me on how dumb I am for doing one or the other. I just figured a big block to handle more than the LS block.

VAformula

iTrader: (8)

Let me rephrase that. I know what each swap involves. I don't mind doing the extra work for a big block. But would there be any noticeable difference between a built big block and a built LSX? If so what are they if anyone knows? Just a question and I've been wondering.

timseitz

I would think one would have many more upgrade options available, then it becomes a matter of how much cash do you have to spend.

SS RRR

iTrader: (2)

For me, it's a matter of weight and hacking into the body to make **** work. I am not a fan of that at all to make something fast. I would definitely chose a big cube LSx over a BBC any day. As already stated it depends on what you want to use the car for and your budget.

ss performance

iTrader: (17)

How big of a big block make a difference. If it is about 540ci or less I think the LS would be better. You can make LS motors up to about 500ci and because they weigh less I thing they have an advantage. That advantage can be over come if you are going to a 632 or someting like that.

As far as the distributor is concerned you can go with a crank trigger on the BBC.

Good Luck

VAformula

iTrader: (8)

Thanks! I didn't know exactly the LSX limits, I think at that rate I'd prolly go a bigger LSX than a huge big block.

Puck

iTrader: (17)

BBC if you want big performance.

LSx isn't even in the same league. Even with similar cubes I'd go with a nice big bore BBC over an LS due to the KILLER cylinder heads.

Negative.

fex77k

iTrader: (2)

BBC 540-605 will get you 1100-1200 easily, and it won't have to turn the RPMS to do it.

96capricemgr

iTrader: (1)

GOAL needs to be considered, you want to go 9s NA an LS will do that, you want to go 8s NA then maybe it is worth looking at a big bigblock. There are dedicated drag cars that don't even need a rollcage they are so slow.

BSmiff

I would say it depends on if you're planning on class racing it or not. Using x275 as an example, even the best LSx nitrous motors are 2 tenths behind the best BBC(572 ci) on nitrous. And that's with a 400 lb weight advantage to the LSx motors. If you're grudge racing I would go with a big inch lsx and run other small block cars. You would have the advantage once you get it lined out.

1961ba427

iTrader: (26)

BBC is where it's at. End of story. That being said, I don't think I'd want to deal with one in a 4th gen unless it was a drag only car. Or at most VERY limited street driving. It's not that I think driving with a bbc would be any harder than another powerplant....I just wouldn't want to deal with the loss of wipers and other issues in a driver.
You can build a pretty decent 454 based stroker for about same $$ as a stock LS2, LS3, L92 pullout.

I think a 406"-434" Gen1 SBC with 24x or other distributerless EFI would be a fun way to go myself. Easy fitment, largest aftermarket support.

VAformula

iTrader: (8)

You're very true, and funny! No, if I was taking the time to put a big block in the it would be a dedicated full drag car. My current firebird is being built to be a street/drag. I just have more experience with gen 1 motors and wanted to see what lsx had on them.

VAformula

iTrader: (8)

It'd be hard to make it a street car. But I would love to make it a full on drag car.

VAformula

iTrader: (8)

Okay. I figured they could handle more. I just really don't know exactly how far a ls1 goes.

Puck

iTrader: (17)

The LS is an amazing platform and will be the cheaper choice to convert to, but for big performance the BBC has too many advantages to ignore.

Tons of cubes, cylinder heads that will make any smallblock blush, blocks are all over junkyards, and even if you are making similar power it's at a lower RPM which is easier on parts and more fun on the street.

On a budget I bet you can make a complete 600hp BBC for around 3 grand using a junkyard 454 pullout. That's less then just a high end cylinder head and valvetrain setup for an SBC. It's the conversion and supporting mods that will cost the big bucks for a 4th gen f-body, the motor is the easy part.

1961ba427

iTrader: (26)

Or use that same 454 core and $3000 budget to build a 427 (439" @ .060" to 447" @ .100") if you want cubic inches and high rpm.

bowtienut

iTrader: (1)

Unless you have 99th percentile capabilities and resources, I'd say this discussion about which could be quickest is just academic.
Either platform can give you more power than you'll put to the track in an 8 or 9 sec drag car.
I think the BBC will be more of challenge to run a given time, just because of its front-end weight and abundance of low-rpm torque (unless you really know your racecar setup), but it is also much cooler IMO