another vortec performance question

[big_mike]

You aren't going to make 760 RWHP in anything and get 21 mpg. You've gotta burn fuel to make that kind of power. If he's getting 20 mpg, he's not making 760 hp while he's doing it.

760 is his true number on the dyno running pump gas with meth injection. Granted if he stayed WOT constantly no he would not get that. But thats a mute point cause similar can be said about any engine. Point is he is making that power at WOT & when driving normally gets 21 MPG, so the power is always there under his foot. Tuning & part selection is KEY though.

I spent many many hours researching & talkin to various shops around the country on different LS set-ups over the years. My only limiting factor is money. I know some of the fastest LS guys in the country from being a member on LS1tech for so long & have seen about every combo tried & tested over the years, minus some of the most recent parts to hit the market. There is a FAR wider array of parts available from places other than mainstream catalog types like Summit & Jeg's also & alot of times have better pricing.

We can argue it all day, but its obvious your a fan of the old school technology over the new stuff. I'm not a old school hater, but I dont ignore the facts I have learned over the years either. The GenIII+ stuff is where its at for power & driveability & the PCM tuning ability plays a HUGE role in making things that are impossible for a SBC easily possible for a LS series.

Just for the record I did look into the options for a Vortec but after all the cost added up for what I wanted or needed to do to support the power, its just not worth it. You can spend the same & have a LS conversion, way easier tuning & better driveability with higher power. But in the end its all personal preference.

 

[ccreddell]

Id like to get my hands on a Motown LS block........

 

[ccreddell]

Just read this in the Dec issue of Chevy High Performance (Whom I believe to be somewhat of an authority on Chevies);

page 29. "These days, opting to build a Mouse motor over an LS small-block probably means that familiarity and practicality both stepped into the boxing ring, and the former won via TKO in the 12th round. With all due respect to the legendary Gen I small-block Chevy, from a horsepower-per-dollar standpoint, it just can’t hang with its LS counterpart. Pricier parts and fear factor used to be the biggest strikes against the LS, but that’s no longer the case. Yank a Vortec 6.0L long-block out of junkyard, swap in a mild hydraulic cam, and you’re looking at an easy 500 hp for well under $2,500. With a plethora of carbureted intake manifolds and MSD’s trick LS ignition controller, you can chuck all that EFI—and the fear that comes along with it—right in the trash. While the Gen I small-block Chevy is the most prolific engine ever conceived in terms of sheer production volume and its impact on amateur and professional racing, each successive iteration of the Gen III/IV design reminds enthusiasts why the General jumped ship to a new platform in the first place."

 

[Aloicious]

why do threads like this always turn into bickering? both platforms have good qualities, but you need to choose a platform and go with it, there is nothing wrong with the GENIII stuff, there is also nothing wrong with the GENIe stuff, they each have their benefits and downfalls that each person will have to judge to see which one would be a better choice for themselves on an individual basis.

however to answer the OP's question, yes, you can switch to a gen III like a 5.3 or 6.0 but if an engine swap is not something you're interested in, there are PLENTY of things you can do to a vortec motor to get performance, and you do NOT need to swap to carb, or get rid of EFI, or anything like that. it all comes down to A) how much performance do you want? (are you building a slightly hopped up daily driver, or a race truck, or anything inbetween)...and B) how much money do you have to spend on it?

whoever you talked to that told you that you HAVE to switch to carb is simply ignorant of the possibilities, when you talk about simple bolt on stuff out of a jegs or summit catalog, yeah they might not list much specifically for the L31 vortec, but just because they don't list something specifically for the vortec, doesn't mean it wont work, or can't be made to work fairly simply, and there are ways to upgrade everything else. really the sky is the limit.

perhaps if you want to let us know what you want first and how much you have to spend, we can help out alot more.

 

[ccreddell]

^^^^Agreed!^^^^

 

[JohnnyBarnett1981]

wow i didnt realize this was going to turn into such a debate lol my truck runs wonderful and only has 158000 miles so i cant really justify swapping out my old trusty 350 for a later model ls engine...however i do value each and every one of your opinions and i really dont think anyone is giving bad advice,i think everyone has reasons for feeling the way they do towards their engine and all of your advice will help me decide which way to go..let me ask anyways..how hard would it be to swap to a 5.3? what would it cost me to do this swap? i couldnt do the wiring because im color blind and id definatly get something crossed..what i hear is the downfall to our ol vortec 350's is the restrictive intake manifolds i really and truely think that if i could find a good flowing intake for this truck and a good tuned 411 pcm and an ls1 cam that it would give a 5.3 a good run for its money and i wouldnt have to perform major surgery in an ls engine swap..you asked what i was looking to accomplish and the money i was looking to spend? i want a dependable daily driver like i have now with the ability hold its own with some of these smart ass rich pampered kids with their hotrods and money id be willing to spend a couple of grand

 

[chevy_man]

You can make power, but be prepared to swap to a carb or the marine intake. A tune and cam would be a good place to start and may be all you need. However, it's my understanding you can't get to crazy without larger injectors which are big $$$.

I just picked up a CCLB K3500 w/L31 and it will be getting a 8.1L as soon as I get done putting the 5.3 into my 88. Nothing like +100hp from a completely stock $500 junkyard motor. Yes, motor swaps cost $$$, but it's cheaper to pick up a motor with sub 100K on it, cam it, tune it, and drive it than rebuilding a tbi or vortec back to stock.

 

[Aloicious]

'eh if you're just wanting a little more power for a daily driver, than you should be okay, the problem with the vortec you have isn't the intake manifold being restrictive (although it kindof is), its the fuel injection being not upgradable. the stock manifold and injectors can support somewhere around the mid to upper 300's in horsepower which sounds like what you're kindof aiming for. if you're looking for more than that, or want to go forced induction of some kind, than you'll need to look at other EFI setups like the marine, or ramjet, or pro flo, etc, etc...but each of those will require some amount of fabrication, wiring, etc to work correctly.

but if you're just looking to get similar to what a stock 5.3 has, you can do that without getting into anything too major. you're not that far off as is, a stock LM7 5.3 from a 2000-2003 silverado put out 285hp and 325ft/lbs of torque...your L31 puts out 255hp and 330ft/lbs of torque stock...so you're only 30hp lower, but you've already got it beat in the torque department....you shouldn't need to do TONS to get your numbers up there, especially since your engine doesn't need a rebuild as it is....you can do things like a cam swap, headers/exhaust, a good set of heads, efan, etc...whatever mods you do, you'll definitly need a tune. even if you don't do anything, a tune will be a benefit. you can look at doing a 411 swap if you want, are you planning on doing your own tuning, or having someone else tune it for you?....also don't forget to do a good full tune up with quality parts if you haven't recently...