I'm debating on wether to go with a mild built 350 with 3.42 gears, or a stock ls1/t56. The money saved going with a 350 and 3.42 would go to suspension and brakes.

Say the 350 is newly rebuilt with a mild cam, headers, high flow cats, decent muffler and ram air intake. With a 3.42 rear end with a 700r4. VS a stock 110,000 mile ls1/T56.

What car would win, and by how much? I think the ls motor would, but I have no experience with either setup.



EDIT: I have decided to go with a LS1/T56 Combo. I currently have the motor and trans. The LS1 motor is being rebuilt, and will have a large cam and full bolt ons. Follow my build thread for pictures and details. https://www.thirdgen.org/forums/theo...g-lsx-t56.html (Pro-Touring LSX/T56 91 Z28 Build)

 

Going with an LS isn't very budget friendly, but if you do it I think you'll be pleased. The Gen III/IV engines are super popular with everyone for a reason, unreal response to mods and easy power.

-"They are a mechanical Robin Hood, stealing hard earned speed secrets from dedicated builders and dispensing them to any mouth-breather with a toolbox."

Power wise, the LS1 with bolt ons (headers, LS6 intake, UDP, tune) will be faster than the 350 you would build with a mild cam. Good luck with you project and budget accordingly either way.

 

Ls1 is faster by far. Like night and day. Which direction is easier for you? Which is more realistic?

 

+1 for ls1

only build a gen 1 if its free


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IMO - TPI is cool if you want nostalgia or a "period correct" car.
There's really no benefit to keeping it over an LS1. I still like them and I still want to build a Lb9 for fun. So it's up to you.

 

To answer your question it really depends on what your goal is for your car?
How much are you looking to spend on the LS1/6 speed? there is a lot of
extra cost to install this motor combo and should be taken into consideration.
And all the money to put that combo together would build a
nice suspension, brakes And a decent 350 sbc.
As for which one would win it depends on more information than you just
gave, like what cam, a mild cam to me may be bigger than what you
consider a mild cam, what compression ratio, what type of heads
, ported, polished, valve size, ,
Its all about the complete package, And what gears does the LS! have.
And what kind of race ?

 

Also depends on what year LS1. 2001/2 have LS6 intake and the best exhaust manifolds. 1999/2000 has the best cam (truck cam). 98's while just as powerful have a computer that's different from 99-02.

FWIW, My 2002 Z28 put down 308/323 at the rear wheels on a dyno. Stock it would run 13.45 at about 105. Your 3rd gen is much lighter than my 02 (tipped the scales at 3400+ with 1/2 tank of gas and me out of it).

After I put a SLP smooth lid and bellows, 3400 stall, 3.73 gears (adjustable TA + weld in SFC's - trust me it needed those when I ran with M/T DR's) and headers with true duals it ran 12.50's at 109. The engine was untouched internally and it dynoed at 343/357 at the rear (after tuning).

Imagine what that would do in your 3rd gen...

 

if you build your 350 it would do well in a 1/4 mile race with the edge going to the ls1 ftw but not by much imo.

price on do an ls swap varies wildly because there are many options.for what i spent on building my 383 hsr cost me the same as my ls1 with the swap parts needed not including the t56.but even my 700r4 needed to be built which was about 1200..my t56 cost me 1600.

you can do a 5.3 and find them really cheap..still keep your trans and save cash that way and have a quick car still with about the same hp as a mild 350 with much better mileage.

the 350 is much easier to do..no wiring involved..direct swap and less time no doubt.i loved torque motors when i was younger and showing off at the lights with my tpi's/hsr setups..but highway dogs.now i cant get enough of that midrange power carrying all the way to 6700 and feel the car streamline without falling on its face..having 6spd helps alot too.

 

If you went full bolt on and ditched the stock TPI, you could run low 13's without even putting a cam in. I am still on stock heads and cam, nothing but bolt ons, and ran 13.5 in the 1/4 with 3.42's. That was on one single pass and I never got another one, so with all things considered on that run (shifting 500 RPM short, bald street tires, only 1K RPM launch, timing retarding 6 degrees all the way down the track), I could run low 13's no doubt in my mind if I shift myself, get my tune issues figured out, and get a harder launch. It also gets 23 MPG cruising.
IMO, if your budget is small like mine, save some dough and get your parts from here, ebay, and craigslist, and go with the 350. You'll end up with a fast car, and that doesn't cost the price LS parts do to beef it up more. I only have about 2K, maybe a little less, in mods because I got them all there. And that is ALL of them, not just motor. Granted, the LS is the king of the hill, but it is just not small budget friendly usually. Plus the 350 is going to be way easier.

 

I have an ls1 with Prc stage 2.5 5.3 heads / 228R cam / Full bolt ons and I love it. Its very mild on the street and makes awesome power. Some how it still gets 20/29 mpg. I havent got it to the track yet so I cant help there.

 

why limit yourself to a ls1?
build a 6.0. heres a common recipe i build. always hooks most first time ls noobs.
relatively economical and very powerful
+.030 6.0 lq4
stock lq4 crank
stock lq4 rods gen 3 pressed wrist pin
with gm ls6 rod bolts or arp(arp are good but not completely necessary, i rip thru 7000rpm on gm rod bolts in.my motor)
speed pro replacement pistons and rings ($400)
ls2 head gaskets.
rebuilt stock 317 heads with new seals, vj on stock valves. .030 mill
thunder racing trex or similar ms3/4. i prefer trex and always buy em when i see em.
for over a decade has been one of the most proven cams. sounds like a demon wot and on spray its just plain insane. 7000 rpm is where it loves to do its work.
best intake your budget allows but a ls6 will do just fine.
ive built various similar combos using 317/243 heads with this cam
i recently sold a local a ls2 trex combo i put together for my own car but ended up selling the longblock. he got it running wirh a super vic and a carb. he was completely blown away by the power. he was only shifting at 5500. i told him to wind it to 7000. the motor was built

 

i have a question? i have a 87 z28 t top with whats supposed to be a 5 speed conversion. it has carb 4 bbl 305. very weak. i want to put in a built 355 pushing 375 hp. and change the gears out. what problems will i run into. im going to put in traction control arms in rear to help stop hopping and axle from twisting. im a truck guy never built a fast car but want it to preform as good as it looks. suggestions much appreciated. thank you

 

a

 

You will need SFC's, and for sure a different trans because the T5 has a hard time holding 200hp not beating on it.

 

As other have mentioned, it is a big project and will cost a lot to convert to an LS motor in a 3rd gen. But the engines have much more potential for power and weigh 150lbs less than an L98 (aluminum LS) and will get better mileage too.

Question is: how big of a project do you want - 1) engine swap or 2) engine swap with new fuel system, exhaust, wiring harness, and accessories?

I have a 400hp mild 350 that runs mid 12's all day and is 100% reliable - but a LS1 can make 75 to 100hp more with (mostly) stock parts and be just as easy to drive.

When I think of a mild 350 (from those I have seen), it brings the idea of a poorly match, poorly tuned 300hp motor that will only break into the 13's...

 

Seeing as im currently undergoing a slightly more than mild 350 build.
350 .030 over flat top 2 valve pistons scat crank lunati cam vortec heads ported edelbrock intake and ported slp runners. Ill add my

as of yesterday when I dropped my block off to be taken .030 over and the rotating assembly balanced ive spent over 5 grand. probably more like 6500 with everything. and Ill tell you this. If i would have known that I was going to spend this much I would have held off from buying parts check by check and I would have pooled my money until I could have afforded a LS1/T56 swap and Would have went that route. ITs the little odds and ends things that get you when rebuilding that 350, and It probably wont stop at a mild build. I started as a new 700r4 trans swap to a Lt1 cam swap with a fresh 700r4. into a built 383. also either route you go....take your time and do it right!

 

If you wanna go fast get an ls1. If you just wanna have a fun car and dont mind getting waxed buy lsx vettes, coyote mustangs and v6 inports build a 350. I wouldnt even build a 383 sbc.

 

I disagree. You can build anything to be fast. with the lengths ive gone in my build I WILL be able to run a LS. however with the amount of money Ive invested into this build I would have rather dropped a cam in a lS1
with a few minor bolt on's and been slightly further than where I am now. If I would have went the route I took on an LS it would have been ridiculous.

It all boils down to how deep your pockets are.

 

ls swaps can be done cheap,you just got to know how to shop. I wouldnt bother getting an ls1 first off..people ask too much for them.Finding a 5.3/6.0 is very common and most are complete with harness and ecu.I got my fbody manifolds for $50..guys are giving those things away all the time.The ls swap mounts/brackets are cheap,find a used ls1 intake complete often aswell for next to nothing,reflash the ecu,get a 255lph fuel pump which you wouldve gotten for a 350sbc regardless.Reuse your existing trans if you want to penny pinch..your going to invest in the 700r4 if you kept it aswell with good stall and rebuild kit.

I dont get why everyone thinks its super expensive to do an ls swap.I spent less doing my first ls1/t56 swap than what I spent on building just my 383 hsr motor alone and the performance wasnt worth the money.

 

You can build a 500hp 383 and be streetable, no problem.

But by the time you get the good parts into the motor, it can get into LS conversion territory - especially if you don't have a lot of SBC reuseable parts to save $.

I do like the sleeper aspect of a SBC - hard to tell if it's a 300hp mild one or a 600hp+ 427; you can even use factory items to look stock... Can't fool anyone with an LS motor in a 3rd gen to think it's slow, lol.

 

Thanks for all of the input guys. I am still torn between the two. I do understand the Gen 1 SBC stepping into LS territory price, performance and reliability wise.

Driving home today I had a Infinite G35 with a turbo ride my butt. When I saw him get in the left lane I floored it, and watched as he passed me. My little 305 had no hope.

I think I am lost because I get such different numbers as far as price go. I have been told I can do a barebones EFI 5.3 swap for 1,200 to 1,500. I have also been told I can't do it for less than 2,200.

 

the more u diy, the cheaper it will be. u have to decide how much ur willing to spend. and be realistic with your fab or diy skill. plenty if ls parts available. many ways to fire and fuel a ls. carb or efi.

 

Building an L98 is not cheap I did it last year with 3:45 9 bolt rear... havent taken it to the track but it will do about 5.7 secs 0-60 untuned. not sure what the estimates to in the 1/4.

I did it because like some mentioned i wanted to be "period correct". My plan wasnt to build an all out race car. The car is fun to drive, it certainly isnt slow. The car sounds great, it is fast enough for me, and the TPI just looks so much better then the LS motors.

I am a big fan of the 3rd gens, so I wanted a L98 TPI, which is what I swapped in from a 5.0 TBI... but make no mistake about it, what i did was nowhere near cheap...

However unless your building a race car id stay true to the generation... Just my

 

Good point insomniac. And thats tue NemeSS-TyranT .

For the moment I'm not too concerned about it being period correct. If I ever feel that way in the future, I could always swap back.

I do have pretty good Fab and DIY skills. I got alot of good experience building rail buggies and that involves TONS of fab and DIY.

At the moment I only have 2k to spend so:

It comes down to keeping the 305 adding headers, a T56 with 3.42 or 3.73's. Possibly some used LS1 brakes.

Or a stock 5.3 with 700r4 trans and 2.73's untill I can cough up more money.

To me the 305 with listed mods seems to be a winner for a fun daily driver street car. And then when I get the money to swap a 5.3 I will have a well balanced car. But I am still undecided.

 

@buggy...id suggest stacking ur pennys until you have enough. However I'm a believer in the go big or go home method. The other day I saw a ls3/4l60e combo on Craigslist for 3500. I could have bought that sold the tranny and bought a T56 conversion for less than I've put in my l98 hindsight being 20/20 I wish I would have saved the cash and built something along those lines. But that's just my opinion.

 

I don't think any one's touched on the MPG savings running an LS1. There has to be a certain number of miles driven beyond which the Ls1 will start paying back for itself in MPG over a built Gen I SBC 350.

 

To keep a 305 and have.performance usually don't go hand N hand $ 4 $ compared to any Ls1 style platform.

 

[
To me the 305 with listed mods seems to be a winner for a fun daily driver street car. And then when I get the money to swap a 5.3 I will have a well balanced car. But I am still undecided.[/quote]

Well some have giving you some really good advice here. If your thinking of doing a ls swap anytime ,I would not worry about modding your 305 at all, the money for headers would be a waist as you'll never get that back Wait on the t56 as the flywheel and bell housing will be different on ls, the only mods I would do is brakes, and gears if you want to for now, other wise save your money for the ls swap. If you still can't decide what to do then flip a coin.

 

I already did. My very mild heads/cam ls1 gets 20/29 with the m6 and will run mid 11's at 120 all day long.

 

I was in the same boat as you my friend, so i decided you know (SR71BLKBRD) "GO BIG OR GO HOME" I said screw the mother for now i just droped a cam and some worked 113 heads along with some other parts i had laying around into a 350 but i dropped all my cash into my suspension. Now im saving for that DIY LSX swap. so i have a mild 350, that handles like a dream i mean full spohn suspension J&M caster koni yellows and Eibach prokit. So now when i do the swap all i have to worry about is the motor tuning and not traction problems. build from ground up is the method to my madness.

 

Or you can build your LSx engine on the side and once completing your build .convert t56 to ls1 t56 , which is easy basically input shaft and bell housing etc. Or sell lt1 t56 to get ls1 t56 then swap your LSx engine

Or keep your current combo use money to buy LSx then when it comes time to swap build your 700r4 while its out bolt up 5.3 then drive into the sunset

You can use all gm parts used and save a ton especially the cam"ls6 cam" very mild and make good power , or you can get a aftermarket one and make even more power "224r or EPS Cam " LSx respond very well to cam upgrades

As long you plan out your combo I mean plan plan plan and do you research as a well thought out package will go faster and be more fun then a thrown together one

it should be fairly easy and always search ls1tech and tho classifieds for parts you need ls1tech is more active on classified side

Make a checklist of everything you will need and what is your end goals and go from there it will make clear of what you want and what combo would be better

cause trust me just cause you have 2k now to spend doesn't mean your not going to spend more $$$ later and that more $$ ,later could be going into LSx so have to look at your overall budget also and not what you want right now right now lol

Got to love modern LSx

 

Theres some good info and advice in here. I am pretty set on the "go big or go home" , mindset. I think I am going to take 3rdgearslammer's approach andjust do a T5 swap and 3.73's. The donor car has some headers I can get for cheap too. Ontop of all of that I just recently did the suspension work. This should make the car a pretty fun street car.

If I wait a year or two I could build a pretty bad a** setup. Maybe a full bolt on and cammed LS2/T56. The stock LS2 is rated at 400hp. With bolt ons and a cam I should be well over 475.

Big goals. I know. However I can manage to achieve it.

 

400hp @ the flywheel, not the ground, be sure you understand that. if you only add 75fwhp with a cam and bolt ons on an ls platform, you're not doing it right.

i ran the numbers on staying sbc, doing a stealth ram, or super ram, etc. like for like it was no question ls power. its more efficient, seals up well, and mine pulls like a freight train from 2500rpms to the 6650 redline that i set.

i like ls power so much, my dd 2wd k5 jimmy is getting a 5.3l/4l60e swap also.

 

i was kinda wondering about that type of set up myself, as far as a semi built 350, with a street fighter turbo 350 and a posi 3.42 gears, i was wondering if the gearing was to low, the car will be done in time for summer, but if that set up is lame, i would like to know now so i can do something about it

 

i ended up swapping to a 9 bolt 3.45 and very happy about it

 

get a lt1 build it 383 stroker..nd 3:73 gears

 

Guys I decided to go with a pretty stout LS1 and T56 combo, so I bought a LS1/T56 pullout and am currently rebuilding it.

The LS1 will have a big cam with full bolt ons. The motor will be backed by a T56, and I will be running 4:10 gears out back. I'm shooting for 400-450rwhp. The car should outrun any "mild" 350 any day of the week, while achieving between 18-24mpg.

Check out my build thread!

https://www.thirdgen.org/forums/memb...g-lsx-t56.html

 

This post is right on the money IMO when your shooting for 450+HP. For a 350 to have a 450-500HP it literally has to be built from scratch to do it right. But lets say you do a "budget" 355 that makes about 420HP. Vortec's, carb, bolt on's, good cam. You still just spent the swap money by either giving it to a builder or a parts vendor and machine shop and you STILL have to contend with the now STOCK new cars. Personally, I would rather just spend the money and have a stock LS1 that has a lot of room to grow than be stuck with a build that cost me that I dont really want.

The only real downside is the down time - It's been almost a year since I have driven anything that "does it" for me. Really sucks!

 

PS: I just pulled the T5 out of my G92 IROC. It will be for sale soon to help provide funds for the T56

 

There still magic to be had with a gen 1 SBC, it would not make since for someone like me to go LS1 at this point because of all the parts I've had for years, its got good heads, cam, and good induction and ignition. It runs very hard. But if I was to start over I would do a LSX without a doubt, great power potential and great fuel economy are hard to argue with.



Mark.

 

I've gotten rid of my gen 1 stuff 3 times now. I still have a pile of distributors, caps, wires, etc, and an early 80's electric choke q-jet. The only thing I miss is the sound, but LS power is so easy and effortless, and putting them together is easier than playing with legos!

I still want to do a square body with an LS...the Jimmy is gone, but I've got my eye out for something killer.

 

From the sound of it, i dont think you will be too happy with upgrading the 305. I think after your done doing that you would probably regret it too. I vote LS all day, and if you dont have all of the money right now just save up. Maybe you could locate a 5.3 locally for a good price, or i find them on ebay all day long for right around 500 bucks. You could always buy an engine and some of the other parts you need now and get what ever else you need as you get money.

 

MyMint92, I'm way ahead of ya. A couple months back I bought a LS1 and T56. The plans are to freshen the motor up with no bearings, rings, and gaskets. Then install a healthy cam, full bolt ons, 4.10 gears, and tons of suspension parts. I should be between 400-440rwhp.




Here's the motor all cleaned up and waiting for the UPS truck to arrive with some internal pieces.

 

[quote=Buggy Disaster;5710160]MyMint92, I'm way ahead of ya. A couple months back I bought a LS1 and T56. The plans are to freshen the motor up with no bearings, rings, and gaskets. Then install a healthy cam, full bolt ons, 4.10 gears, and tons of suspension parts. I should be between 400-440rwhp.




Oh wow. I just read your build thread yesterday haha. Looks really good.

 

Coming along nice brother!

 

Very interesting thread. I'm tempted to wait until I have the budget for an LS. Obivously LS motors win overall, but I'm still getting the impression the TPI motors have more low end kick. For off the line, or stop light to stop light thrills, would those of you who have driven both go with the TPI motor or the LS?

 

tpi's off idle is awesome. but i bet i could put 4 or 5 cars on my old L98 with my 6.0l.

 

so let me ask you L98 vs a LS1. Same car same weight etc... 50 yards off the line whos in front?

 

that's a loaded question. stock for stock would be close, with bolt-ons the ls1 would be out in front no question.

honestly, the only thing that would make me go back to a gen 1 sbc would be for the sound. everything else about the ls platform is better.

 

hmm thats interesting too. so you think say a magnaflow L98 with headers sounds better then a magnaflow LS1 with headers?

i was always under the impression the LS1 was better all around...


however the L98 is a better lookin gmotor hands down... if it matters