LS vs Big Block
03-22-2013, 02:51 PM
#12
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LSX power any day over big blocks. I am a bit biased though...
This is the last one I built. Last I heard, it was still kicking a$$ in Canada. When you can pull an engine down with 100k miles, nearly a thousand lbs of nitrous ran through it, and still has cross hatching showing in the cylinder bores it tends to make you a believer. I got hooked on them when they first came out and built more than I can remember. As reliable as an anvil (except for the LS1 sleeved big bore engines I dealt with).
This is the last one I built. Last I heard, it was still kicking a$$ in Canada. When you can pull an engine down with 100k miles, nearly a thousand lbs of nitrous ran through it, and still has cross hatching showing in the cylinder bores it tends to make you a believer. I got hooked on them when they first came out and built more than I can remember. As reliable as an anvil (except for the LS1 sleeved big bore engines I dealt with).
03-22-2013, 04:45 PM
#13
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i have a ls 418 that pulled 642 hp on 93 pump gas, with a carb ,in a chevelle .BUT i dont think the torque numbers would hold up on low end like a bigblock . in a heavy boat , large boat i would still take my bigblock .
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03-22-2013, 08:23 PM
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i guess im old school but in my opinion there is no replacement for displacement. a NA 572 or 598 with a 1050 carb will make atleast 750hp on pump gas. even if your boat is simi small the extra torque from a big block is huge. a punched out and slightly stroked version 632 will make 800-850hp with tons of torque on 93 gas. there is also the option of aluminum big block for weight. i cant tell you the difference in price though cause ive always gone big block. just my 2 cents.
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03-23-2013, 12:47 AM
#19
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First of all let me state that I am skeptical of the results claimed in that article. Second, it is true they did not specify what type of fuel so I guess it is possible it uses race fuel. That said if the numbers in article are accurate, I think it would be difficult for BBC to match those tq numbers without 600+ ci. Keep in mind they are claiming over 700 ft/lbs of tq from 4000-5900 rpms with a peak of 754 ft/lbs at 4500rpms. And they claim over 600 ft/lbs for the entire pull, of course they do not mention where they started the pull, but with peak tq at 4500 and pk HP at 6200 I seriously doubt it is lacking anything down low. Also the claimed number are allegedly through an 850 carb. That is impressive. No doubt this motor was a high dollar build, including the RHS tall deck block (not sure if that is the billet one or not), high dollar crank and rods, but the heads are relatively cheap out of the box, that carbed intake can be had for less than $500.00, and a ignition controller (not the distributor conversion they are using) can be had for $300.00.
03-23-2013, 01:22 AM
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Before the LSx crowd gets the panties in a bunch, I have owned a couple in automotive applications. One of my younger brothers has a LS2 based forged 402 ported LS3 headed .620ish cammed nasty iin his 05 GTO. Every time I drive it I think man, this thing is stupid fast. It pulls low 11's in the 1/4 and he drives it to work almost every day. He has 50K on this build and other than being really hard on valve springs ( square lobed hydraulic rollers do this) it has been super reliable.
GM never built an LSx over 427 CI for a reason. The LSx engines can be spun up and produce great HP but that alluminum block will not hold up in a marine application. Big tourqe LSx engines are built off of the iron block LQ9 truck engines and have lots of boost applied. They can handle that well in a automotive application but a marine application put stresses on an engine from idle on up that the LSx engines were not designed for. When you start talking about aftermarket blocks and unlimited CI's everything changes but yet stays the same. What it really comes down to is cost to repower. Most people can reuse all of their accessories when repowering with a healthier BBC. Making the swap to an LSx engine will require all new accessories, i.e. exhaust manifolds, accessory drives and brackets, engine pounts, bell housings etc. This will double the cost of making the swap.
GM never built an LSx over 427 CI for a reason. The LSx engines can be spun up and produce great HP but that alluminum block will not hold up in a marine application. Big tourqe LSx engines are built off of the iron block LQ9 truck engines and have lots of boost applied. They can handle that well in a automotive application but a marine application put stresses on an engine from idle on up that the LSx engines were not designed for. When you start talking about aftermarket blocks and unlimited CI's everything changes but yet stays the same. What it really comes down to is cost to repower. Most people can reuse all of their accessories when repowering with a healthier BBC. Making the swap to an LSx engine will require all new accessories, i.e. exhaust manifolds, accessory drives and brackets, engine pounts, bell housings etc. This will double the cost of making the swap.
