LS vs small block

[WyattTX]

I notice everyone seems to be doing ls swap nowadays. They are great modern engines, but this has me thinking. How would the best small block with the best EFI system, and paired with the best drive train, compare to a ls with all the same items? What would be the better engine if both were carburated? Does the ls aniquate the small block? These may be a dumb questions to some, but I would not call myself an expert, but rather a novice willing to be enlightened. Thanks.

[mongocanfly]

Everything about the LS is a engineering advancement and a step above the smallblock..I used to not think that until I've owned a few..I'm a believer now..as far as myself ill never own another carb engine if I can avoid it

[AcampoDave]

I wouldn't build a small block to be a rival to an LS. I would build a small block because I like it for what it is. I grew up with small blocks. I like them because I have that nostalgic connection to them. I get that they are outdated... but hey so are flatheads and they won't keep up with a small block but they still have their appeal to the people that have that connection to them. Small blocks and late model engines are very different....hell I think my late model 4 cyl tachoma might take my stock 283 v/8 in a drag race.

[BR3W CITY]

Cooling, fuel dispersion, head port design, manifold design (and composite material tech), machining tolerances. All better on LSx stuff.

[PGSigns]

When I did my 66 I used a vortec head L31 crate engine, an edelbrock intake and carb, a msd e-curve, had a 700R4 built, bought the lockup controller. That was over $4500. The 5.3 LS I have sitting on the floor with the 4L60E and the harness to run it was $2200. Granted it has 31000 miles on it but in the end it will be 1/2 the cost and run twice as good. I am an old school guy but I drive my trucks to work every day and put a lot of miles on them so engine swaps for me will be LS!
Jimmy

[Tom]

Originally Posted by PGSigns

When I did my 66 I used a vortec head L31 crate engine, an edelbrock intake and carb, a msd e-curve, had a 700R4 built, bought the lockup controller. That was over $4500. The 5.3 LS I have sitting on the floor with the 4L60E and the harness to run it was $2200. Granted it has 31000 miles on it but in the end it will be 1/2 the cost and run twice as good.

Thats a bad comparison. A used vortec drivetrain would be much cheaper then the used LS drivetrain you just quoted. A new LS drivetrain would be absurdly expensive.

OP- For me the answer is simple. To get LS head flow rates I have to spend thousands on aftermarket heads. So LS is better for power. For towing, I'll take a GenI small block anyday, which is why I have a 98 instead of a 99+ driver truck.

[mongocanfly]

I had a gen1 smallblock in my 81..swapped to LS..I tow heavy loads behind it and I'm here to tell ya that smallblock couldn't touch my LS with a load..I could have spent more on that smallblock than my LS swap cost and I still don't think it could touch the LS for power, towing and mpgs.
And the LS seems to run forever..I put 285000 on my 99 5.3 and never turned a screw on it except for a water pump..so yea..I don't see a problem comparing a 31k mile LS to a crate smallblock
Its just all in what your looking for.. (old school) smallblock or (new school) LS

[WyattTX]

Thanks, I see there is a price to pay for old school simplicity. One more question I cant seem to answer, is why do some put a carbuerator on a ls? Does it improve performance, simplify things, or what?

[mongocanfly]

Most carbd LS motors are because a guy is going for a smallblock look and/or doesn't want to mess with the electronics..its expensive to carb a LS and it kinda defeats the purpose of having injection..all the benefits of injection are what makes the LS better

[PGSigns]

The 5.3 with a set of headers and a good air cleaner will make well over 300 hp and and close to 375 pounds of torque that is there from the crack of the throttle that NO stock L31 with the same parts will come close to. I have the L31 with a cam and efi and my brother has an 02 truck with a 5.3 and just a cat back and he can out run and out tow me any day.
Jimmy

[SavageGrizz]

What Mongo said.... Running a carb is for those who don't want the "extra" electronics, but you have to run an MSD box anyway (unless you do the EXPENSIVE manual distributor option which is mostly for racers who aren't allowed to run spark boxes) or for the look of an old school rod. The LS blocks don't have a mechanical fuel pump like the SB/BB's do, so if I'm already having to run an electric fuel pump; I may as well take it one more step and enjoy the benefits of EFI. On the other hand, if you already have a good carb just laying around you can save a bit of coin and minimize your electronic foot print; but the performance difference is negligible. "Drive-ability" with EFI is incomparable to a carb though.

I'm terrible at re-jetting carbs and am much better at adjusting fuel tables and AFR's with mouse clicks and key strokes ;-) FAST and Holley both have decent and "relatively" inexpensive throttle body based fuel injection systems which sit right on top of the carb manifold.

If my junkyard motor still had a decent set of injectors and the truck plenum didn't break in shipping, then I would probably just re-use it, but for $1250 I'm gonna give the Holley Sniper kit a go.

[Tom]

Originally Posted by PGSigns

The 5.3 with a set of headers and a good air cleaner will make well over 300 hp and and close to 375 pounds of torque that is there from the crack of the throttle that NO stock L31 with the same parts will come close to. I have the L31 with a cam and efi and my brother has an 02 truck with a 5.3 and just a cat back and he can out run and out tow me any day.
Jimmy

I can go up hills in my 98 with 1000lbs in the bed locked up in 4th gear at 80mph. Simple freeway overpass hills make any 5.3L I've driven drop a gear unloaded. Sorry but the LS's don't have torque unless you wanna scream, in which case sure they'll do better. Most peeps like a relaxed ride towing long distances though.

[mongocanfly]

Each to his own I guess..I've been pulling heavily loaded trailers (6-8000 lb) for over 30yrs..I've gone thru my fair share of smallblocks..I've never owned a smallblock that can hold a candle to my LS..a bigblock or diesel is a different story in torque... but this is smallblock vs LS.
I'll take my LS any day over a smallblock.
as far as a downshifting LS goes you have to consider these newer trans have a multitude of gears in them (my newest truck has 6) so yes a auto is going to be more inclined to hunt a lower gear..my tow rigs have been mostly manual trans though so I pick when I want a downshift..

[crazy longhorn]

Originally Posted by WyattTX

Thanks, I see there is a price to pay for old school simplicity. One more question I cant seem to answer, is why do some put a carbuerator on a ls? Does it improve performance, simplify things, or what?

Look at the dyno runs....the carbed LS, will give up some of the magic /vs the fuelie.....but every dyno run that I have seen, will pull more top power with the carb I dont usually get involved , in the carb /vs fuelie, the fuelie guys dont like that carb on that LS mill! The LS is one tough engine....mine has 140,000 on the bottom/ fresh top (just a surface & grind & a set of springs). No cats, dual/H pipe, & will scoot my old 4200 lb truck around on the pavement, about like that old gen I stroker did! Longhorn