LSX vs Big Block

[2012-2SS]

Well my boss is huge old school big block guy and I can't make a convincing enough argument as to why the LSX family of motors are better.

He put out a hypothetical budget of $12k to build an all out LS and all out big block. He says he could have 750-800 NA hp no problem out of an over 500ci big block. Now I've never researched building an LSX engine, but is that same power even possible out of a naturally aspirated LS given a budget of $12k?

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[Bad70supreme]

Probably not, its hard to beat big power on the cheap with any old school big or small block. The one thing though is, no way those old motors are more reliable or will last remotly as long at that power level. LSX based engines are much stronger... unless he builds on a aftermarket block, but then he would be most likely over budget. One thing for shure, none of those engines make the power of an LS with simple boltons and a cam! To make cammed ls3 power out of a basic stock big block chevy, would take a full performance build!

[VADER SS L99]

With a all out race motor big block all the way but if your talking about streetable power the LSX will make more power while being streetable. Like if you were to compare say a LSX 454 build vs a 502 BB while still being streetable the LSX would make more power and probably be lighter. If there were no limits and it was a dedicated track motor the BB would blow the LSX out of the water just due to the fact that you can get BB's past 540ci, huge solid roller cams, heads and intake. This is of course talking about NA and not FI.

[Bad70supreme]

Ya all true but your not building no 540ci out of a real big block from the 60s! What your talking about is a full aftermarket big block. Not sure what this guy thinks, but a ls engine requires allot less work to make some seriouse street power compared to a stock 454. But really once you build a solid short block, say a 468ci with some wicked heads and a roller cam your going to have a pretty nasty engine! You can't go wrong with a stock ls3 short block making over 500hp and not worry about throwing a rod threw the motor! If I had to choose a stock short block 454 or a ls block to work with... No question I am going with an ls! Once you go into the short block it really don't matter any more.

[2012-2SS]

Ya he was talking about an aftermarket block, all forged rotating assembly, aftermarket heads and a roller cam. But stock for stock ability the LS definitely takes the cake.

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[Bad70supreme]

If he can get all that for 12k then he has a point. I never looked into a max effort lsx before, my guess its gonna be more then 12k! But no dought a ls based engine can achieve the same power but I assume not as cheap.

[Jims Mongoose]

From what I understand the LSX is basically an LS7 but with a cast iron block more room to punch it out.

It is the engine I would just love to plunk into my Camaro. I believe the 454 LSX crate engine is 750 horsepower from Chevy. Unfortunately I thinks it's about $15000.

Is that correct? How much better engine is the LSX than the LS3. I am considering a 1LE and making it my project car for the next bunch of years. Eventually bringing it to 700 HP +. Is this feasible, normally aspirated and still have a fairly streetable car?

Can the LS3 be punched out to 454?

Jim

[Bad70supreme]

An ls3 can be stroked into 427, if you go lsx iron block your adding weight. You can do a ls3 427 with high compression, heads, big cam, victor intake with a dominator carb and make some crazy N/A power! I don't have any experience building a ls engine like that myself, my stuff was old school until now! I want to go 427 with mine down the road but keep it streetable.

[Bumblebee2012]

Originally Posted by Bad70supreme

Ya all true but your not building no 540ci out of a real big block from the 60s! What your talking about is a full aftermarket big block. Not sure what this guy thinks, but a ls engine requires allot less work to make some seriouse street power compared to a stock 454.

Why not a 540 or 572 out of a factory big block? My 2 bolt 460 with Eagle 521ci rotating assembly and EX-514 heads/intake was just under 900hp on the dyno. I followed that up with a Ford Motorsports A-460 block at the same 521ci with same heads, intake and carb but with a stupid big cam and showed 1070 on the dyno. Those were with single Dominators on cast aluminum intakes, no drugs, no forced induction, and on gasoline. You have to mess up to only hit 700 from a cheap 460 stroker with reworked SCJ heads and Victor. I have a 700hp Ford 460 (offset ground crank to 501ci) that was run for 4 years and is now sitting on an engine stand because it was to small for our use. It was used on the track and on the roads for those 4 years. That can slip into my Chevelle some day just to mess with the heads of folks at car cruise!

Many of the guys that sled pull run high 500's for ci out of iron 460/454 blocks. It's very common. Anymore, if your not 800-1000 hp, there is no use throwing a chain on back. Stay home.

That said, power is easy. Long life can be a whole different story. But keeping a traditional BB around 700 can be done fairly easily while being hobby streetable.



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[Bad70supreme]

I have heard of 500ci out of stockers, I am not big on Chevy motors. I did Oldsmobiles for almost 15 years and we could not get much bigger then 500ci without sacrificing the integrity of the block to much! I would rather go aftermarket when it comes to building something that big, but like I said my BB Chevy knowledge is limited to street builds. The problem with the big cube Oldsmobiles was that the block would stress to much, crank would flex and you would end up with trash if the motor was not built spot on! Even then allot of engine failure has happen when pushing the limits. What do I know I never built a BB Chevy like your talking, that's pretty darn impressive to say the lest!

[Jims Mongoose]

I really in agreement with your course of action. I would like to do the same. The reason I want to bore it out and keep it normally aspirated is like the old muscle car rumbly feel of the instant torque engines.

Is it possible to run on pump gas, and have a normally aspirated bored out LS3 run decent on the street at 700+ crank horsepower?

[Bad70supreme]

I would think you could get pretty close with a stroker setup, definitely mid 600s and street friendly! I need to start doing my research, but 427 ls3 with around 650-700 would by my goal as well.

[VADER SS L99]

Originally Posted by Bad70supreme

I would think you could get pretty close with a stroker setup, definitely mid 600s and street friendly! I need to start doing my research, but 427 ls3 with around 650-700 would by my goal as well.

You can use a ERL resleeved block for 427-454 ci. Only way I would do it for 427 or larger displacement with the LS3 block.

[Jims Mongoose]

Originally Posted by VADER SS L99

You can use a ERL resleeved block for 427-454 ci. Only way I would do it for 427 or larger displacement with the LS3 block.

thanks to both Vader and Bad70. Are you saying that even going to 427 from the current 372 Cubic inches will leave me with an unreliable engine?

My plan was as follows:

Bored to 427, thats 54 more cubic inches and shaved heads for increased compression(not sure how much). This should be good for 100 to 120 horsepower.

Headers, cam, cold air, tune should be good for another 100 to 120.
That gives me at best 240 horsepower more for 666 horsepower. A little short of my goal, want 750 at the crank. Am I being to conservative on my estimates or just going in the wrong direction.

Jim