WHAT MAKES MORE HP ON A JUNKYARD 4.8L LS? CARBS OR EFI? EDELBROCK PERFORMER RPM & 750 v TRUCK EFI 

I know most folks are stuck on power, power, and more power! But what I want to focus on is a balance of power and “decent” fuel economy. So my question/challenge to you Richard is about fuel consumption. Maybe you can start adding that matrix into the videos or create a couple videos on fuel use per a given combination for equal amounts of dyno time 💁🏼‍♂️ Thanks for all that you do sir!!!!

Carbs have always seemed the right choice for me because I love the simplicity. Very little is needed to make it work and get really close on the tune up.

I am really enjoying this series on this junkyard 4.8, especially the NSR Truck Norris cam test. I still love building old school 283's for nostalgic reasons, and I have a fresh one on the stand for my 66 C10. However, a good friend recently dropped off a good used 2009 truck 4.8 and said, "Change the camshaft and put it in your 66". Thanks to you, I can see that my friend is right.

I never get tired of your 4.8/5.3 testing

I like the way you tested this. If I had the complete factory EFI, I would run it. I have no idea of the factory electronics is swap friendly or not. But I have a hard time following the PROGRAM, I would try the carb set up because I am weird like that.

Thanks Richard. A true dual plane to a truck intake test. Not how I expected it to turn out!

Richard man you keep me always watching to to see how it works out!! I really enjoyed this test,I think a 600 cfm carb would maybe have worked better on the little 4.8????and maybe a performer intake if they make one 🥴I hope you do a street 5.3 with a turbo and the NSR cam 🙏would also love a head gasket thickness comparison,Quench I mean!I really love the test you do I don’t even watch anyone else testing 😉

when i saw these power curves i was mortified! then i realized my phone screen wasn’t cracked and i was very relieved

That AF curve is typical of newer carbs with big air bleeds and big jets to match. You could tilt it to the right by going down in jet and air bleed.

I cant wait to see some V10 Triton other guys testing

Rich. Your last results comparing dual and single plane carb intakes to the stock ls3 intakes was surprising. I'd have no idea the dual planes could beat a medium runner efi intake to 4500rpm. Basically in daily driving ram a good deal more torque. The higher ram operations could have likely been improved with porting and plenum work. On the single planes they were just coming alive at 5500 or so. I'm sure they would allow operation to 9000 on that large displacement.

Brilliant and real stuff as the usual. .. Thanks Again and keep up the Great work....

Would be interesting to see what a Quadrajet would do as well..

Interesting. Time for a test of carb versus EFI using the Truck Norris NSR cam. 👍

I enjoy these videos, but in the end, I’ll take EFI for street applications every time. And I’m an old buzzard that was brought up on carbs. EFI was like a gift from above …

I’m an efi guy but I’d take the carb curve that’s impressive that it made constant power

Try a Q-jet, or a 650 Holley. The carb would E.T. better, on a drag strip, because you could use a lower rear gear ratio. The EFI probably has better fuel milage. Nice video.

If you want the carb look, just go Holley sniper EFI 4br (or two even) and get the much better tuneability of efi with the look (and feel/sound from my experience) of a carb without all the nuisance.

I would like to see a dual quad carb setup. I feel like it would be more fair due to the fact 8 barrels for 8 cylinders for even fuel distribution. That’s my thought at least and would love to see how the results look!

I've had both a LS2 with CNC ported LS3 heads with a 226 duration intake 236 duration exhaust 600 lift on intake and exhaust aftermarket camshaft with a GM single plane intake with a Holley HP 850 carberator redlines at 7200rpm had this setup from 2008-2021 now have a GM performance LS3 495 horsepower crate engine with CNC ported and milled LS3 heads with a 219 duration intake 228 duration exhaust with 525 lift intake and exhaust with a 102mm throttle body and sheet metal intake with ZL1 injectors and fuel pump redlines at 6600rpm tuned and runs on E85 the LS2 carberated engine made 540 horsepower at 6700rpm with 470 foot pounds of torque at 5200rpm at the crank the LS3 fuel injected on E85 made 520 horsepower at 6200rpm and 495 foot pounds of torque at 5000rpm at the crank so it's down 20 horsepower vs the carberated engine with a more mild camshaft but with the injected engine from 3000-6200rpm is up 25 foot pounds of torque in some of the rpm range 30-35 more torque than the carberated LS2 but the carberated LS2 was better 6200rpm up I've had the injected LS3 now for 11 months and so far l really don't miss the carberator and the headaches of tuning it once a year and replacing 80 dollar spark plugs every 12-16 months because the carberator needs to be tuned after 1200 miles on the injected LS3 running E85 after inspecting the spark plugs after 1200 miles they look close to new after 1200-1500 miles with the the carberated LS2 it's time to change the spark plugs if you want it running it's absolute best if your going to be street driving the vehicle and idling at stop lights the fuel injection is better but l can see a carberator working well on something that is more of a drag race vehicle that will need more maintenance and tuning the throttle response with the carberator tuned was really good but l think the throttle response of the fuel injection is slightly better and so far has been untouched now 11 months

I'm guessing the reason the engine lost power at 13.2 on the carb setup is simply down to cylinder to cylinder fuel distribution. You probably got a few cylinders up in the high 13's/low 14's and that was enough to knock a couple hp off. Much less of an issue on EFI.

Hey Richard, Swapping a EFI TB with injectors on the dual plane intake would be intresting and easy. Does better fuel control add any HP or TQ? My guess not much but what is causing the shorter runner intake to make better power to 4000 rpm over the longer runner truck intake, seems to go against what you would think.

wow the low tq being better on the dual plane versus long runner efi also showed up in this test.

I'd like to see how it'll do with a throttle body injection like an MSD or Holley along with that dual plane manifold. 🤔

You'll get even more power from efi with a tbss/nbss intake. It's cheaper to go fuel injection especially when pulling everything from the yard. You'll have everything down to the harness/ecu to run it. And as far as vats being turned off, there's even free ways to do it now. If you go carb, then you still have to buy the carb, intake, and msd box. About an extra 700 plus

I'm reading up on how to build an engine dyno because of you. 🤣🤣

Very interesting test. I am surprised to see that power is already dropping off at 13.2 : 1 AFR I presume that the factories are compelled to set AFR at the stoichiometric ratio of 14.7 :1 to minimise emissions. I would like to see you do power tests at AFR values ranging from 14.7 to 14 , 13.5, 13.0 and 12.5. This should be fairly easy to do just by altering the block of no.s in the fuel table and everything else held constant. Can you arrange this. This would give us some appreciation of what the factories have to deal with. Regards, John

Maybe 450cfm carb would have been less sensitive to jet changes and the vacuum signal would have helped throttle response

Great video as usual! Thanks for the time you spend on all this. Question. What happened to making the different combinations different colors on the dyno graph? Made it a lot easier to tell what hp or torque line belonged to what combination.

I’m wondering if you ran into fuel distribution issues with the carb/dual plane setup. If you had 8 EGTs or 8 O2s you could check for it, but hardly any street installation is going to be set up that way. Multipoint EFI is going to get the fuel itself pretty even, but there may be air distribution issues to cause variance, with all the twists and turns, both air and fuel might be disturbed on a carb setup. Still, interesting results, especially the different rpm peaks in the torque/hp curves. Thanks, Richard!

I like to see a adaptive intake manifold like the 392 hemi but nobody makes one for the LS engines

My take-away from this test is that the LS Performer intake manifold is not the best at cylinder-to-cylinder fuel distribution. That is evident by the noted loss of power when attempting to use anything leaner than 12.5:1 Air/Fuel mixture ratio. It is easy to achieve with port fuel injection. It is difficult to design a wet-flow intake with cylinder-to-cylinder distribution to be near optimum, which is required to run the leaner mixture ratios. When one cylinder tends to be leaner than the rest, you must richen the overall engine's mixture ratio to bring that one cylinder into the safe/power mixture zone. It is not necessarily a huge detriment on an engine being built for performance but it is a detriment when looking for fuel efficiency as well if that is a primary consideration.

I would be interested in the truck efi compared to duel plane/Holley sniper TBI. I like the thought of the old school look with efi setup. Especially with the gold Holley body.

It would be interesting to see this comparison with a slightly stronger cam with a smallish lsa, maybe the dualplane could give driveability as well as a strong midrange. Just a thought. 🙂

When it's getting down to performance.... it would also be nice to see the basic petroleum use on each setup, as M.P.G,s ,I know without the specimen being placed in a actual demo vehicle it may be more challenging to crush numbers...or may be easier to say which one burns lesser fule.. thanks again...

A tunnel ram may have been closer to the long runner truck manifold.

Other tests I’ve seen you do show the carb performing better due to charge air cooling of the fuel. This test probably has more to do with the intakes than carb or efi but I was surprised the efi long runner intake performed better at higher rpm so maybe a better explanation or test might be required to clear everything up.

Hello Richard, Considering an engine and tyranny upgrade for my 4wd LS 2000 Tahoe with iron block 5.3. Have already upgraded suspension, brakes and 18" wheels. Interior is great shape too. Has the bi-fold twin rear doors, not a tail gate. Goal is 375 to 400 hp with good low end torque, improved efficiency and teamed with a new 4L80. Considering swapping 3.73 to 3.23 differentials. Can you recommend long tube header size and exhaust. Result being the same or slightly better performance with much better highway mpg at lower rpm. Carb versus EFI Testing of the 4.8 answered one if the questions I had. New full size SUVs are bonkers money these days. Thanks for your real world videos. Keith

"I saw dis video but, I wanted to ask Richard a question ?" 😋

I would love to see a stock gen 3 5.3 run. With just a edelbrock pro flo Carb Style efi systems

I wanna see more 6.0 bigg cam. Big nitrous stuff

Try the 1995 4AFE and the classic 22RE

Why don't you use a different color for each test on the power graphs with a small index in the corner? It would make it a lot easier to understand for everyone.

Starting video, my bet is carb, because cooling effect. Lets see if was right. 😁EDIT interesting results.

I think when the two runs times are compared the EFI will be a fair bit quicker witch means the EFI basically kicked the carb’s ass a bit, very interesting to see the difference the carb did well I think 👍🏻🏁

I'd try the torker intake

👍💪

Thank you! Is there an aluminum block 4.8??

I would like to install this set up on my 85 k20 suburban on 35s 4:10 gears with 700r4 . I'm wondering if I use stock 1200 rpm stall converter

I’d like to know what jets you ended up with?

very interesting.

I'd like to see single plane I bet the graphs get closer to truck intake.

Has anyone ever tested performance with a 2 barrel on an LS? Particularly a 4.8?

I would like to see a larger carb tuned right to see if it would match the efi with more airflow.🤔

Your the best

@Richard Holdener Any suggestion on replacement lifters? Are Delphi any good being so much cheaper than the OEM Style LS7 lifter?

I'd like to see how the gen4/TBSS would compare.

Rich I never see where a 4 hole spacer helps an ls engine in any case unless you want all bottom end power however a 1 inch open spacer is worth 1 to 2 tenths in the quarter mile on every ls we worked on and tested at the track

I would like to see the same test but now with a cam designed for a carb motor instead of the stock efi cam.

My guess is EFI.

Like, share, subscribe, ring the bell. Do all that stuff. Tricky Ricky needs a new pair of shoes

Have you ever made an open plenum intake into a 4 chamber plenum. Using a small opening to balance intake pulses. Increases velocity? Maybe help throttle response?

Do you think that these results would be exaggerated on a 6.0l with a cam and heads?

How about a 4.8 with stock fuel injectorsand rail, a mid rise intake, and a 4150 style throttle body?

Hey Richard which Holley 750 did you use? Is that a vacuum secondary or mechanical secondary? I've had better luck with a vacuum secondary with a metering block for secondary jets. Also a slightly lighter spring in the secondary diafram depending on the camshaft. Do you think you would had better results by using a 600 cfm carburetor vs the 750 cfm carburetor?

Please do a high compression 305 Chevy build. I want to know what a small strokey engine would do on the minimum requirement for E85 [70%]. Love your content. [edit: just how high could you safely go on E70? 13:1,14:1?]

Maybe 4.8 would have made more power up top with a 650

Hi my name wayne and i Have a 1971 chevy c10 350 engine 4 barrel holley 650 i need your opinion if You can I appreciate it go with efi siniper 2 or swap ls 5.3 engine let me Know thank you

Posting before watching.. . . The performer rpm for the ls isn't very good, my money is on the stocker here.

as efi have `perfect` air/fuel ratio, shouldn`t the computer based system perform better at every rpm. how long(and varied) did the efi get to run before the vs test

Do the same test and add nitrous 👌🏾

Hey Richard, I know this question will probably get me some hate but maybe not... Do you have an opinion in regards to the Edelbrock performer AVS carbs and have you tested any on some LS carb setups? Thanks sir!

I would like to see what combo (cam, heads, intake..) would be best for low to mid pulling power. NA and turbo, 5.3, 6.0, 6.2.

Smaller carb would have helped, losing velocity

Just out of curiosity, I’d love to see this test repeated but with a short runner efi plenum and a single plane carb plenum

Is this a tuning issue? Maybe tuned efi will get that little bump of power low down?

Test test... quench.

Do a coyote motor same way

Ever going to do a performance engine or just cheap junkyard cam efi LS combo's?

Did the 4.8 like the 4-hole spacer? Or did it not make a difference in power

Richard could you test a tsp 216/220 low lift versus a truck norris

Is the relatively small truck throttle body causing any issues for the EFI? It seems to me a 750 CFM carb would have the ability to flow a lot more air (whether the engine can use it or not) than would a 78mm TB. Not sure how it would affect it overall ... might even hurt the bottom end torque more than it already was in comparison to the dual plane ... would be interesting to find out, though.

Is there anyone here that is knowledgeable in building ls turbo systems and is near Seattle Washington that can tune a new 6.0 ls?

Ok rich....i have an 87 gmc k10....5.7 tbi....im getting oil in the coolant...but no coolant in the oil....i found 1 guy online w similar issue....he found out it had some hairline crack between to oil galleys and cooling passages....oil pressure is higher then coolant so the flow went hi to low....but i cant understand is when engine is off....the oil goes to zero and the coolant stays 15 psi til it cools over several hrs.....why it dont leak into oil?? Anyway...im thinkin 454.....what years...junkyards...price should i be in? Thx

Why would you compare a known bad intake with a good intake 🤔. Also previous carb videos you’ve done show the carb setup made more power So now you make this showing the opposite

I’d really like to see a carb comparison between the 750 and a 625 or so, I wouldn’t be surprised if there was pooling going on with lowered velocity. I bet there’s 30hp there

I’m curious if this would take a 600-650 carburetor instead of the 750???

Can you do a test with a ls3 intake ona 4.8/5.3 with adapter plates

I rather have peke power at lower rpms below 5k

I’m doing a ls 5.3 lm7 swap carbed on my 85 c10 with a msd 6014 and a electronic fuel pump, anything else I need to make it run as a fun daily?

Curious to know what kind of timing table u are running on the carburetor setup I have a 6.0 with a Carb

Hey Richard I have a 5.3 with stage 2 cam, single plane msd6014 and with a 625 demon carb my only problem is that it diesels on 87 but not on 91 I tried the timing on with 87 and no luck I have no problem running 91 but it’s kinda pricy and wanna use 87 instead any suggestions would help thank you!

Richard, do you think a carb cam, 108 or 110 LSA, would have helped the carbed numbers much?

Would a smaller carb or different carb make a difference?

Hi Richard, with carb do you run more timing advance?

Please PLEEEAAASE get an external mic. I hate the echo

Because of the way the heads flow could a single plane intake work better?

Can you test a retro ls intake setup on that 4.8

I know that they make good mules, I'm getting sick of ls motors.

What was the AFR curve of the EFI setup?