Carb SBC vs TBI SBC vs Gen 3 LS reliability

[GoToGuy]

Want a little better life out of your Vortec , get rid of the plastic poppet injection for upgraded Delphi, Standard, fuel injection. That alone could make a world of difference.
Not a big investment for potential good return. Good luck!

 

[slow_c1500]

Fixing the existing vortec is my plan, but I am just thinking ahead for future swap ideas when this engine starts having serious problems that would warrant a rebuild/replacement.

 

[Scooterwrench]

The techno geeks are going to tell you that electronically controlled fuel injection and ignition is going to be the most reliable and give you the best fuel economy. I run pre 88 350's with Q-jets and mechanically advanced HEI's and get great fuel economy and longevity. The last motor I built and tuned had over 500,000 miles on it before it died(blew)in a mud truck.
The one that will be going in my 91 1/2 ton only has 10,000 on it and gets 19mpg in a 3500 pound car. I'm hoping for 17 in the truck with the overdrive tranny.

Don't expect to pull a carb or distributor out of the box,bolt it on and have it perform. You have to tune them to make them work for your application. Not any different than tuning a CC system except you will have do some actual work and maybe get some dirt under your nails.

 

[L31MaxExpress]

Thank you guys for the responses! At this point I can probably rule out carbs. So between the TBI small blocks and LS engines without AFM, I am getting the sense that the LS is just the best option. I have also heard that the LS engines seem to have less leaks and less electronics/sensor failures. Is this true as well?

IMO, less electronics to fail on the SBC vs the LS. 350 has far more low-midrange torque than a 5.3L where you drive 95% of the time. Fuel mileage of the L31 350 is just as good if not better than the 5.3L.

 

[98 Nitro]

My L31 has 225k has never been rebuilt, does not burn oil and runs great so just as reliable as a LS motor.
However I still prefer carb for an old Chevy muscle car easy to tune a Holley carb and it's not a major pita to change a fuel pump and it is so much more cost effective than an EFI system.

 

[slow_c1500]

IMO, less electronics to fail on the SBC vs the LS. 350 has far more low-midrange torque than a 5.3L where you drive 95% of the time. Fuel mileage of the L31 350 is just as good if not better than the 5.3L.

When you say the SBC has less electronics, do you mean TBI specifically? The vortec SBC has about the same amount of electronics as the LS. That’s why the TBI small block could potentially be appealing, there are less electronics that can go bad, and it’s simpler.

 

[L31MaxExpress]

When you say the SBC has less electronics, do you mean TBI specifically? The vortec SBC has about the same amount of electronics as the LS. That’s why the TBI small block could potentially be appealing, there are less electronics that can go bad, and it’s simpler.

No the Vortec is still more simple. No drive by wire, 1 coil vs 8, less wiring, fewer connectors, etc. Vortec has 2-3 extra sensors compared to a TBI and very few ever give issues. My sensors were nearly all stock GM until I put the 383 in. I had a knock sensor and MAF fail in ~20 years. I changed the 2 pre-cat 02s as preventative as well when I put headers on it because I had them out in my hand.

 

[slow_c1500]

No the Vortec is still more simple. No drive by wire, 1 coil vs 8, less wiring, fewer connectors, etc. Vortec has 2-3 extra sensors compared to a TBI and very few ever give issues. My sensors were nearly all stock GM until I put the 383 in. I had a knock sensor and MAF fail in ~20 years. I changed the 2 pre-cat 02s as preventative as well when I put headers on it because I had them out in my hand.

I see, however some early LS’s are drive by cable. Are failures with the individual coils very common on LS engines? I guess that’s something you trade for distributor failures on small blocks.

 

[L31MaxExpress]

I see, however some early LS’s are drive by cable. Are failures with the individual coils very common on LS engines? I guess that’s something you trade for distributor failures on small blocks.

I replaced aomething like 2 sets in the 3 years I ran them. Very common failures atleast on a van.

My distributor issues were caps and rotors, MSD fixed that for me, got 5 years out of the last one.

 

[slow_c1500]

I replaced aomething like 2 sets in the 3 years I ran them. Very common failures atleast on a van.

I guess I can see your point about the vortec being simpler now, especially considering the ignition system.

The vortec really only has 4 failure points: cap, rotor, ignition coil, ICM.

The LS has 8 individual coils, so theoretically more failure points.

You also mentioned that the vortec has less wiring and connections than the LS, what do they have that the L31 doesn’t?