SBC vs LS 5.3/6.0/XX with EFI. I know this subject has been covered over and over but I have a little different scenario. I have a ram jet 350 long block in my car with a Holley stealth ram EFI manifold and 58mm Holley throttle body on it. this is a vortec head, roller block, 1 piece rear main engine. I still have this huge debate going on in my head on going LS since its seems to be what everyone is doing. My goals in this build is to have a good dependable, fuel efficient engine that has a decent amount of power. I am not building a drag car, I would say it’s more of a pro touring type of car that is decently fast and handles great so I am not looking for 1000hp track machine. what I am 100% sold on is having EFI and a overdrive transmission.
Ok so I have been reading the debates online between the two platforms, most of them are comparing an old carbed 350 from the 70s to a LS. Arguments include the EFI, gasket sealing with newer silicone gaskets, roller cams, serpentine accessories, HP out of the box…… all good points when comparing to an old school SBC. ok so the 350 I have built is specked out at 350hp with a ram jet intake, I have a less restrictive Holley stealth ram intake on mine, being a late model it has 1 piece rear main seal and all silicone gaskets and previously never leaked a drop, it has a OEM serpentine setup that GM sells for their crate engines, it came with a stock roller cam and has roller rockers that I upgraded to.
Arguments to make for sticking to the SBC and why I don’t want an LS. I already have a full 2 ½” true dual exhaust setup with stainless shorty headers and flowmaster 40 series. I like the shorty headers for clearance under the car and not needing to use an aftermarket cross member, I have not seen LS shorty headers available. I can stick to using a traditional transmission that includes allot of choices, I do not have to buy a new transmission the way I sit, I do not have to adapt the engine mounts, I do not have to track down a pricey oil pan just to clear the cross member, I do not have to buy expensive brackets to get the front accessories onto the engine. I will not have to adapt a speedometer to the electronic transmission. I will not have to adapt a drive by wire throttle pedal . I do not need to shorten the driveshaft. I do not need to sell off all of my SBC stuff that I spent a good amount of money on in the last decade for a fraction of what I purchased it for. what I have now is unique, more than likely won’t see another setup line mine at a local show especially if I run the ECU and I am thinking about doing.
Arguments for the LS. Its modern, its fuel efficient, it can make a ton of power with simple mods, 6 bolt mains if you want to go all out, it’s a little lighter than a SBC, more top end power. (In stock form the way it will go in if I go this route will likely only be 350ish HP and comparable to my current 350)
Transmission wise keeping the SBC, I can stick to my 200 4r(442 version), no drive shaft mods, no cross memeber swapping, no issues hooking up the speedometer, no flex plate adapting, no possible drive shaft shortening…. I am not sure but I worry that the shifter attachment may be different on the newer 4l60e/4l80e. there are ways to use the old school transmissions but again more money in adapters for cables and what not.
To add another argument for me to keep the SBC, EFI connection has come up with a kit that is affordable that will allow me to add a 24X relector wheel to a SBC making it possible to run an LS ECU and harness on a SBC and also gain coil per cylinder ignition which means no more distributor. I can pick up a ECU and harness from the salvage yard, I have been told I can have the harness gone through and dummied down for 150 bucks for an ls, this would be the same deal, 300 on a tune +/- and 250 for the efi connection kit and I am at 700 bucks for the entire EFI setup installed and tuned on what I have currently. If you wanted to do this same setup on existing SBC you can get these manifolds for around 300 new, I bought fuel rails for 80, you can get a throttle body from a stock TPI car or buy an after market one for a couple hundred off ebay and have a budget efi setup.
I have read multiple articles that has claimed that the traditional SBC has more low end torque but the top end and steady torque curve on the LS is what makes them so much better power wise. My thoughts are I am not drag racing so does this do anything for me? what do I have to gain? I am after more off the line power than top end.
As I sit now, I have minimum to spend to be up and running with at least a 350hp EFI SBC/200 4R that’s already currently installed in the car. if I sell it all off, it will likely take me months to get it all gone, I might have 2500 bucks sitting in the wallet when I am done if I am lucky and then I start all over with a LS that I will likely be at the 5-6000 dollar mark by the time it is all the way I want it.
Is there really any good reason to go LS if you currently have a SBC? I kinda feel like people are quick to write of a traditional SBC to go after the new thing when a SBC can more than likely be done cheaper even from scratch. what I have now, the ram jet long block is identical to a late model vortec 350 with the exception of the ram jet cam that can be had for around 100 bucks used on ebay. You can pick up a vortec 350 for cheap out of the salvage yard and rebuild them at home for not much cash and drop it in place of an existing SBC. The reason I bring this up is because I have a second g body with a 355 carbed engine in it now. what if you have say a 383 stroker with aluminum heads that is carbed and already at close to 500HP? Does a LS swap make more sense than going to EFI?
Ok so I have been reading the debates online between the two platforms, most of them are comparing an old carbed 350 from the 70s to a LS. Arguments include the EFI, gasket sealing with newer silicone gaskets, roller cams, serpentine accessories, HP out of the box…… all good points when comparing to an old school SBC. ok so the 350 I have built is specked out at 350hp with a ram jet intake, I have a less restrictive Holley stealth ram intake on mine, being a late model it has 1 piece rear main seal and all silicone gaskets and previously never leaked a drop, it has a OEM serpentine setup that GM sells for their crate engines, it came with a stock roller cam and has roller rockers that I upgraded to.
Arguments to make for sticking to the SBC and why I don’t want an LS. I already have a full 2 ½” true dual exhaust setup with stainless shorty headers and flowmaster 40 series. I like the shorty headers for clearance under the car and not needing to use an aftermarket cross member, I have not seen LS shorty headers available. I can stick to using a traditional transmission that includes allot of choices, I do not have to buy a new transmission the way I sit, I do not have to adapt the engine mounts, I do not have to track down a pricey oil pan just to clear the cross member, I do not have to buy expensive brackets to get the front accessories onto the engine. I will not have to adapt a speedometer to the electronic transmission. I will not have to adapt a drive by wire throttle pedal . I do not need to shorten the driveshaft. I do not need to sell off all of my SBC stuff that I spent a good amount of money on in the last decade for a fraction of what I purchased it for. what I have now is unique, more than likely won’t see another setup line mine at a local show especially if I run the ECU and I am thinking about doing.
Arguments for the LS. Its modern, its fuel efficient, it can make a ton of power with simple mods, 6 bolt mains if you want to go all out, it’s a little lighter than a SBC, more top end power. (In stock form the way it will go in if I go this route will likely only be 350ish HP and comparable to my current 350)
Transmission wise keeping the SBC, I can stick to my 200 4r(442 version), no drive shaft mods, no cross memeber swapping, no issues hooking up the speedometer, no flex plate adapting, no possible drive shaft shortening…. I am not sure but I worry that the shifter attachment may be different on the newer 4l60e/4l80e. there are ways to use the old school transmissions but again more money in adapters for cables and what not.
To add another argument for me to keep the SBC, EFI connection has come up with a kit that is affordable that will allow me to add a 24X relector wheel to a SBC making it possible to run an LS ECU and harness on a SBC and also gain coil per cylinder ignition which means no more distributor. I can pick up a ECU and harness from the salvage yard, I have been told I can have the harness gone through and dummied down for 150 bucks for an ls, this would be the same deal, 300 on a tune +/- and 250 for the efi connection kit and I am at 700 bucks for the entire EFI setup installed and tuned on what I have currently. If you wanted to do this same setup on existing SBC you can get these manifolds for around 300 new, I bought fuel rails for 80, you can get a throttle body from a stock TPI car or buy an after market one for a couple hundred off ebay and have a budget efi setup.
I have read multiple articles that has claimed that the traditional SBC has more low end torque but the top end and steady torque curve on the LS is what makes them so much better power wise. My thoughts are I am not drag racing so does this do anything for me? what do I have to gain? I am after more off the line power than top end.
As I sit now, I have minimum to spend to be up and running with at least a 350hp EFI SBC/200 4R that’s already currently installed in the car. if I sell it all off, it will likely take me months to get it all gone, I might have 2500 bucks sitting in the wallet when I am done if I am lucky and then I start all over with a LS that I will likely be at the 5-6000 dollar mark by the time it is all the way I want it.
Is there really any good reason to go LS if you currently have a SBC? I kinda feel like people are quick to write of a traditional SBC to go after the new thing when a SBC can more than likely be done cheaper even from scratch. what I have now, the ram jet long block is identical to a late model vortec 350 with the exception of the ram jet cam that can be had for around 100 bucks used on ebay. You can pick up a vortec 350 for cheap out of the salvage yard and rebuild them at home for not much cash and drop it in place of an existing SBC. The reason I bring this up is because I have a second g body with a 355 carbed engine in it now. what if you have say a 383 stroker with aluminum heads that is carbed and already at close to 500HP? Does a LS swap make more sense than going to EFI?
