LS VS Oldschool

[Fox80]

If I spent the money for "059" 58cc Vortec heads and intake for my 305, it would make 300 emission legal HP, not sure what the MPG would be though. Of course a 180 HP 305 with 9.5 CR will respond to mods better than a 8.5 CR LO 305. Many, but not all factory SBCs have lower CR than LS1s, higher the CR the more efficient and powerful the motor will be but costs more to set up that way. A 76 350 block is going to be poorer made than a 80s SBC block, even a 80s 305 block. No matter what, a good engine isn't going to be cheap regardless of brand or type.

As for LS swaps being legal, that can get tricky. For a LS swap to be completely legal, it must have every piece of OBD2 low emission gear swapped over from the donor car. Such as having a OBD2 port installed under your dash and wiring your service engine soon light with the LS's management system, having all the cats, and the more complex EVAP system, nothing deleted. Carb LS swaps into a G body are illegal since they disable most of the LS's emissions systems, a big no no.




I agree with most of that, to me using an LS style motor then switching over to a carb setup almost defeats the purpose, as I stated above GM didn't reinvent the engine with the LS series, it is still a crank 8 rods and 8 pistons, the actual bore/stroke combos in all the LS motors can be reproduced almost exactly in a SBC setup. If you look at both motors apart they are very similar, take away the equal separation of the intake runners and the coolant divorced intake and they are almost identical. Neither of these items have been proven to make more power, and like I stated above the setup to fire the coil packs alone could rebuild a mild SBC. If you decide to use an LS in stock form, they can be bought cheap, good thing because the fuel injection, electronics, motor mounts, headers, and pulley set ups will set you back a lot of money. These motors do not have enough advantages to me to justify the added cost over a standard SBC motor, yet. Like I said if the price on parts continue to come down they will replace the SBC in time but they have not yet. Also from the above quote, how do you foresee raising the compression on a motor costing more money? A properly built motor will be zero decked off the crank centerline, and the heads true cut off the valve guide, so if you wanted to remove another say .045 to raise the comp. ratio it wouldn't cost more, if you were not machining the block or heads a simple thinner head gasket would work, also same money. Compression ratio and smooth runner tracks have been proven time and time again to be the two easiest and cheapest ways to make more power and better efficiency

 

[Clone TIE Pilot]

If I spent the money for "059" 58cc Vortec heads and intake for my 305, it would make 300 emission legal HP, not sure what the MPG would be though. Of course a 180 HP 305 with 9.5 CR will respond to mods better than a 8.5 CR LO 305. Many, but not all factory SBCs have lower CR than LS1s, higher the CR the more efficient and powerful the motor will be but costs more to set up that way. A 76 350 block is going to be poorer made than a 80s SBC block, even a 80s 305 block. No matter what, a good engine isn't going to be cheap regardless of brand or type.

As for LS swaps being legal, that can get tricky. For a LS swap to be completely legal, it must have every piece of OBD2 low emission gear swapped over from the donor car. Such as having a OBD2 port installed under your dash and wiring your service engine soon light with the LS's management system, having all the cats, and the more complex EVAP system, nothing deleted. Carb LS swaps into a G body are illegal since they disable most of the LS's emissions systems, a big no no.




I agree with most of that, to me using an LS style motor then switching over to a carb setup almost defeats the purpose, as I stated above GM didn't reinvent the engine with the LS series, it is still a crank 8 rods and 8 pistons, the actual bore/stroke combos in all the LS motors can be reproduced almost exactly in a SBC setup. If you look at both motors apart they are very similar, take away the equal separation of the intake runners and the coolant divorced intake and they are almost identical. Neither of these items have been proven to make more power, and like I stated above the setup to fire the coil packs alone could rebuild a mild SBC. If you decide to use an LS in stock form, they can be bought cheap, good thing because the fuel injection, electronics, motor mounts, headers, and pulley set ups will set you back a lot of money. These motors do not have enough advantages to me to justify the added cost over a standard SBC motor, yet. Like I said if the price on parts continue to come down they will replace the SBC in time but they have not yet. Also from the above quote, how do you foresee raising the compression on a motor costing more money? A properly built motor will be zero decked off the crank centerline, and the heads true cut off the valve guide, so if you wanted to remove another say .045 to raise the comp. ratio it wouldn't cost more, if you were not machining the block or heads a simple thinner head gasket would work, also same money. Compression ratio and smooth runner tracks have been proven time and time again to be the two easiest and cheapest ways to make more power and better efficiency

I didn't mean building a motor with more CR would cost more. I meant buying a crate motor that has more CR would cost more since GM and others usually charge more for a motor with a decent CR.

 

[Fox80]

Sorry, yes that I agree with although that doesn't make any sense either I guess

 

[85GPLef41]

Got my swap done legally... though it depends where you live. Colorado is almost as bad as Cali.... damn tree huggers!! I will admit it was easier to pass a ls engine vs a carbed sbc for performance. I'm not knocking eon sbc builds but I did try to build a vortec headed sbc but imo I wasn't gaining a whole lot vs just skipping the lt1 and going for the ls1.. NOW that I did it "legally" im ok not doing a carb and trying to stick to originality.I do have a plan for a older G body carbed build with a big block!! IF YOU CAN build a high HP engine then why not? but if you want power, decent mileage, drivability then I would choose a ls series engine. Though a carb looks like it belongs there..

 

[Poncho61]

I agree that technology is amazing. Less cubes, more efficiency, equal or better power in a lighter package that lasts more miles. But, I do not own a single rear wheel drive chevy product. A couple of newer montes that wife and daughter drive. I own /drive nothing but Pontiac. So for me as appealing as new tech is, it'll never fully happen in one of my drivers. Sad, but Pontiac is expensive as hell to build and make comparable power to the new LS based stuff, so its a wash when people say the LS is expensive. Pontiac aluminum block=$4K, Heads anywhere from $1500.00 to over $3000.00. Looking at that, I've already spent LS money for a block and heads. Throw in the internals and I paid for the car the LS came out of too. But my pride or stupidity, depends on whos talking, LOL, says it has to be Pontiac in my Pontiacs. And not the chevy with the Pontiac plastic engine covers like the late model GTOs, Firebirds etc had. Real, low tech 1950s based technology at way more than 1950s pricing. LOL

I've owned Pontiacs since 1979, have a couple still that I bought in 1980. Swapped old school Pontiac engines into ford trucks, (easier than you'd think). My middle son talks about buying a camaro. Being a Pontiac guy means my F body ride has a bird on it somewhere, and when he mentions the other, I ask him where he'll park it, since it won't be in our drive. 😀 .

I suppose if I ever bought a 4th gen LS based Firebird, it would stay that way,,,,,,,,,,,,,for a while. The third gen birds I have will be Pontiac powered here one day. The V6 in the one is already disconnected and ready to pull so I can fab up the mounts for the Pontiac engine. The 80 GP in my avatar has the boat anchor small Pontiac V8 265 that will give way to the 400 Pontiac on the stand in the garage right now. No LS ever put into one of my vehicles by me tho. Yeah, thick headed old man. 😀

 

[jdietschweiler]

Ive done the swap from sbc to ls and from ls fi to ls carbed. My perspective is that if you dump the conversion money in the sbc, you will have a bad *ss sbc. But when if you switch, the possibilites are way more with the ls.

 

[Randy_W]

trying to build up an OLDs motor to compete with an LS will not happen, the design flaws of the OLDs platform have kept people as a mass from using them for big power since the onset, so the aftermarket has not embraced them with the wealth if aftermarket performance parts the SBC enjoys

I understand and agree with your point ONLY if you are going for a max performance build. I will make more power per dollar with a moderate 455 Olds build that should break into the 11's. If you need to go faster than that in a G body then get out the checkbook and spring for a $12,000 LS7 crate motor.

More power than what? I'll guarantee you a 6.0 LSx can be built with more power, cheaper than a 455 of any brand if you're starting from scratch and talking about a streetable engine. It will also drive better, get better MPG and be lighter, making it brake and handle better. Not trying to be an *ss, I love the old stuff, been a Pontiac guy all my life, love the BOP engines, but truth is what truth is, times have changed.

 

[Silent viewer]

I'm an old guy and I'm hard headed, but, if you want to go fast, stay light and not spend a fortune, go LSx. I hear how expensive they are, well a stock 5.3 with a tuned pc will out run a mildly built 350 and can be be bought for $750-$1000 in the salvage yard. Unless it was an original car or some special show piece, I'd never build another big block, and I ran a pair of 540's in my Donzi. The new engines are better, period. Years of R&D paid off, and each revision gets better.

another fellow performance boater! I tried to message you but I don't think you have that activated? in my boat its BBC all day long, in my cars I have SBCs and from here on out its LS period if I buy another motor. boat engines are a totally different animal to build and you need the cubes. heck LS motors are even starting to get popular in performance boating

 

[Randy_W]

I'm an old guy and I'm hard headed, but, if you want to go fast, stay light and not spend a fortune, go LSx. I hear how expensive they are, well a stock 5.3 with a tuned pc will out run a mildly built 350 and can be be bought for $750-$1000 in the salvage yard. Unless it was an original car or some special show piece, I'd never build another big block, and I ran a pair of 540's in my Donzi. The new engines are better, period. Years of R&D paid off, and each revision gets better.

another fellow performance boater! I tried to message you but I don't think you have that activated? in my boat its BBC all day long, in my cars I have SBCs and from here on out its LS period if I buy another motor. boat engines are a totally different animal to build and you need the cubes. heck LS motors are even starting to get popular in performance boating

My messages seem to be working?! Anyway, if I were building an offshore boat today, I'd be building lsx motors for it. Those big inch factory blocks and the flow of those heads combined with a 500 lb savings of the stern are going to kill those old big blocks. I already know guys that have gained 8-12 mph using LSx motors in 100+ MPH boats, that's a helluva an increase, as it takes the rough equivalent of 50 h.p. in a 7500 lb boat to gain 2 mph at 70, with no other changes.
Yes, boats are totally different animal, it's like pulling a bulldozer uphill at wide open throttle all day. They need to run fatter than a car with optimal timing for the flow characteristics of the heads, have the torque curve still strong at whatever rpm you're running and still not over heat or detonate. Then there's the drives and props...

 

[L92 OLDS]

trying to build up an OLDs motor to compete with an LS will not happen, the design flaws of the OLDs platform have kept people as a mass from using them for big power since the onset, so the aftermarket has not embraced them with the wealth if aftermarket performance parts the SBC enjoys

I understand and agree with your point ONLY if you are going for a max performance build. I will make more power per dollar with a moderate 455 Olds build that should break into the 11's. If you need to go faster than that in a G body then get out the checkbook and spring for a $12,000 LS7 crate motor.

More power than what? I'll guarantee you a 6.0 LSx can be built with more power, cheaper than a 455 of any brand if you're starting from scratch and talking about a streetable engine. It will also drive better, get better MPG and be lighter, making it brake and handle better. Not trying to be an *ss, I love the old stuff, been a Pontiac guy all my life, love the BOP engines, but truth is what truth is, times have changed.

Randy, no offense taken. I'm listening and intrigued by your response. Can you put a list of costs together for swapping in a new (or very low mileage used) LSx 6.0 into your 85 442 that will produce 500 hp / 500 ft-lbs? I would like to see the real numbers. Make sure you include everything needed to do the swap correctly (no Jim Bob shortcuts with a welder and gas ax). We could make this a sticky for others on the site.