EFI SBC vs LS Motor
 

Just looking for some specifics on why to do one vs the other. Currently I have a 350 SBC & T-10 with the following mods:

• Eldelbrock TEC 200 Aluminum Heads
• COMP Cam 12-612-5 Solid Lifter Cam
• Roller Rockers
• Ceramic Coated Headers
• Holley Competition 750 cfm
• MSD Ignition
• Super T10 4 Speed Transmission
• Center Force Clutch
• Scatter Shield
• Hurst Comp Shifter
• OEM Forged Crank
• OEM polished rods
• TRW pistons w/ floated wrist pins
• Balanced rotating assembly
• ARP Head Bolts & Fasteners

So I've been really interested in doing an LS swap, even have tossed the above setup for sale, but a friend says since I've already got some decent parts on this motor why not just EFI it?

Now my goal is 700whp with a blower - granted this will be a while down the road, one step at a time.

From what I've read, with no specifics other than newer technology, the LS motor does everything better. From fuel economy to making power and the important one drive-ability. A big one for me is the reliability and turning the key and having it start, without pushing the pedal 4 times etc. Yes the 350 has never let me down but I'm nervous every time it cranks for a min, ha!

So why not do an intake manifold and EFI on the 350 SBC? Why should I swap to the LS?

To you guys that have done the EFI on the 350, what parts have you used?

Thanks!!! :y0!:

I am no expert, but from what I have read, it seems to me that when it comes to breathing, the LS engines are really more akin to a Big Block, and that's the big difference between the old Small Block and the LS engines.

You can make the same power in a more reliable package with an Ls.

The irony is that with all the interest in LS conversions, the SBC parts are becoming very inexpensive. While I continue to monitor LS conversions, at least for the forseeable future I will be running a SBC. I am considering a throttle body EFI to replace my Holley double pumper at some point.

I've thought about it. If you do this you still have to do all of the other 'fuel' parts. Tank/pump/regulator/lines etc. At which point if you decide to go LS it'll already be done, ya? Or am I missing something here?

I thought about converting my built SBC over to fuel injection too, or even procharging it but my compression is a little to high at 10:1

It's like Todd said, the LS does it more reliably. Even with your goal of 700whp, the LS will be more reliable though it's arguable what constitute reliable at that power level. If you were wanting a lower power level, say 500 or so at the wheels, I'd say stay SBC because with a blower that's not difficult or really even pushing limits and a good EFI system will allow for good drivability.

The other thing to keep in mind when building a forced induction car is where the power comes on. As an example, to me, a Procharger is a terrible choice for a pro-touring car or really any car not being drag raced. Go drive one and you should realize very quickly that it does not produce a linear power band and they have terrible lag(I know nothing about their new intelligent design so maybe that's changed) which is not enjoyable when going on and off throttle and around corners. So achieving your goals with boost and how much boost will be needed also has to be taken into consideration. At 700whp, the LS will do this better as well needing less boost which will allow for an engine that isn't piss poor when not under boost.

I would recommend building towards the ultimate goal from the get go or else you'll be redoing lots of stuff. If going for 700whp is required to you, get an LS now and call that part done.

Thanks for the response.

However, I'm not sure about your 'lag' description. Superchargers are far more linear than a turbo is, am I missing something here? Is it the that style supercharger, a Procharger that's not as linear?

I've own supercharged and turbocharged vehicles, mostly BMW's and the supercharger on that one was far more linear and constant than the turbo. On a road course you better know exactly when that turbo will spool or you'll be going sideways.

Correct me where I'm wrong! Thanks!

Yes, it's because it's a Pro-Charger. They need RPMs to build boost just liek a turbo typically does. A Whipple, Magnacharger/Harrop/Eaton, and Kenny Bell blower won't act like that typically(the wrong cam or too big of a blower can cause some lag though). They are known as positive displacement blowers. They are listed in a volumetric size because that's the equivalent "displacement" they add to a motor. Basically, they make the motor act as if it's bigger than it really is from the throttle response to how much power they end up making. However, a Pro-Charger makes great power and is an excellent supercharger. It's just not making power where or how it needs to be made in order to make a good pt style car. That's my point, be careful where and how you make your power when reaching for that 700whp goal. That's why I think you'll need to plan your build from the get go if 700 is the goal. Last thing you'll want is a 700whp motor that is no fun to drive the way you want or intend to drive.

500-600 is much easier to build in stages starting with NA because it's fairly easy to reach those numbers reliably with low boost levels. 700 at the wheels puts you at about 850 flywheel. Going from NA to that level boosted reliably is not so easy due to the increase in boost needed among other things. This is of course my opinion. I'd highly recommend you work with a builder before you do anything if seriously reaching for the 700whp mark. I'd also recommend you focus more on how you want the engine to respond and where the power is made than simply shooting for a number if enjoying the drive is the main goal.

A car for you to check out that may be of interest is one built by member RS302 or something like that. He started with a 1st gen that was Ford 302 powered. Once he blew that motor, he went to an LSx with twins. The throttle response is unreal on that car. I love it. He makes great power and runs it on 87 octane. It's a neat build.

There's just no comparison between a SBC and an LS motor.... if you're looking for a great "up grade" from what you have now - just buy an LS motor or be sorry you wasted your money on old skool stuff. You'll be money ahead with the LS.



The HP figures you're throwing around require a LOT more expense than just the motor. I won't waste my time explaining this now - cause you're not there... but anyone on here will tell you this.

Thanks for the info guys, didn't know that about the ProCharger, good to know!


It sounds like I might end up going turbo after all. Those other style chargers introduce a decent amount of heat/soak issues due to their placement for the style driving I do, sounds great for 1/4 mile though but I don't do that except for fun with friends. I'm for sure not chasing any 1/4 numbers though I'd much rather spend my time on the street and road courses.

Sounds like for what I want I do just need to go ahead with an LSX style swap and well my built 350/tranny.

Good info! I'll look more into the comparison of procharger vs turbo setup now.

I've very familiar with what would need to be done to the motor, especially for the type of driving and power, but had no clue of that ProCharger and the way it reacts. We'll see if I decide to built the motor or not for whatever I decide. After this research I'd been thinking of doing everything else, other than the motor, first. Mini-tubs, front and rear subframes etc. Decisions decisions!!

Thanks!