383 vs 376
Thread Starter
TECH Apprentice
Joined: Jun 2014
Posts: 305
Likes: 1
From: Houston, Texas
383 vs 376 Well Guys I have the unfortunate blown motor. My car has the LS6 block and if the liners were good and block was good I was considering throwing a forged bottom end in it with a 4.000 stroke. -2cc dished pistons ect. I am on a slight budget so at first I'll probably keep my factory top end (241's and LS6 intake). Get a decent cam to take advantage of valve reliefs and some larger injectors.
The other obvious option, especially when you factor in a good set of heads, is the LS3. I understand the Larger bore size is definitely an advantage but when it's all said and done, I am shooting for 500 rwhp for a daily setup. I just want something reliable that makes good power all motor and decent economy when just cruising (car is a 6-speed).
The LS3 route would require a conversion kit, different manifold, and a couple other nick naks. Is it worth the extra coin?
Opinions welcome. Just trying to make sure I spend money wisely and get value for it. Doesn't always mean the cheapest option, just means best HP/Dollar. Your opinions are appreciated.
The other obvious option, especially when you factor in a good set of heads, is the LS3. I understand the Larger bore size is definitely an advantage but when it's all said and done, I am shooting for 500 rwhp for a daily setup. I just want something reliable that makes good power all motor and decent economy when just cruising (car is a 6-speed).
The LS3 route would require a conversion kit, different manifold, and a couple other nick naks. Is it worth the extra coin?
Opinions welcome. Just trying to make sure I spend money wisely and get value for it. Doesn't always mean the cheapest option, just means best HP/Dollar. Your opinions are appreciated.
TECH Addict
Joined: Jul 2013
Posts: 2,189
Likes: 123
From: Portland, Oregon
For just a driver car, simple 383 stroker kit, have Phil weld and port your 241's, use the ls6 intake you already have.
For a racecar, the ls3 is the obvious choice.
Remember, if you go to the rectangle port heads, you need more gear out back, and that will greatly impact the driveability of the car.
For a racecar, the ls3 is the obvious choice.
Remember, if you go to the rectangle port heads, you need more gear out back, and that will greatly impact the driveability of the car.
The LS3 gets tragic mileage, my SS gets the within 1mpg of my 2005 Z71 Crewcab on my normal commute.
I honestly believe the rectangle port heads for the 6.0/6.2l motors were a way to REDUCE lowend torque and load on the drivetrain (for the 100K warranty) under normal driving while still making a nice peak number.
I started this thread.
https://ls1tech.com/forums/generatio...hetically.html
I don't think the rectangles are good for much other than limiting torque for a light car or making a peak number that isn't actually backed up on the track..
If 500rwhp is your goal you semingly fall into the later category though. 500rwhp is deep into the 10s with a mediocre chassis and that rollbar you need will kill you on the street should your head hit it when you get into a "daily driving" accident.
IMO scale your HP goal way back, for a true daily that gets some sort of economy I would aim for a maybe 430hp cathederal port motor with decent compression, if you can get a 6.2l shortblock I think that an excellent option.
I love the SS but the LS3 is NOT one of the car's strong points makes a peak number without the broad powerband that should support it. Kind of sad when a 415hp car dead hooks on street tires with no sidewall. On the SS forum someone said it is "almost like AWD" as hard as it is to get it to spin the tires without using the brakes.
I honestly believe the rectangle port heads for the 6.0/6.2l motors were a way to REDUCE lowend torque and load on the drivetrain (for the 100K warranty) under normal driving while still making a nice peak number.
I started this thread.
https://ls1tech.com/forums/generatio...hetically.html
I don't think the rectangles are good for much other than limiting torque for a light car or making a peak number that isn't actually backed up on the track..
If 500rwhp is your goal you semingly fall into the later category though. 500rwhp is deep into the 10s with a mediocre chassis and that rollbar you need will kill you on the street should your head hit it when you get into a "daily driving" accident.
IMO scale your HP goal way back, for a true daily that gets some sort of economy I would aim for a maybe 430hp cathederal port motor with decent compression, if you can get a 6.2l shortblock I think that an excellent option.
I love the SS but the LS3 is NOT one of the car's strong points makes a peak number without the broad powerband that should support it. Kind of sad when a 415hp car dead hooks on street tires with no sidewall. On the SS forum someone said it is "almost like AWD" as hard as it is to get it to spin the tires without using the brakes.
If I were in your situation and needed to stick to a budget, I'd fix what I had (stroked to 383ci
)....and would keep the 3.90 gears.High HP numbers are cool to brag about, but you can lose those bragging rights with 'slow' runs down the 1/4 mile track! Your proposed 383ci setup won't hit the peak numbers of a LS3 headed motor, but it will have the torque advantage up to about 4500 (or so) RPMs. And that will win you a lot of track respect!
My 429ci with 3200 stall gets 22mpg HWY (cruise set at 75mph) and city/HWY combined I'm at just under 16 MPG. I think that's pretty good for being modded as I am.
Maybe a tune is needed to improve your fuel trims....
KW
Last edited by KW Baraka; Nov 20, 2015 at 02:37 PM.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
For a daily go with the LS3, and I'm not a rectamgle head guy either on the smaller gen IV stuff. But with the bigger bore it leaves you with more head options down the road should you build it.
You can still make it work pretty well with rectangles if you go light on the intake (less than 10cc larger) and heavier porting on the exhaust. That way you can get away with only needing 3-4 degrees bias exhaust duration and allow more room for a tighter LSA, this retaining some driveability. The rectangle heads need more overlap relative to duration to retain tq and still make good power compared to cathedrals. Just keep duration in the low to mid 220's and run as much compression that's safe, up to ~11.5:1 on 93.
Jason
You can still make it work pretty well with rectangles if you go light on the intake (less than 10cc larger) and heavier porting on the exhaust. That way you can get away with only needing 3-4 degrees bias exhaust duration and allow more room for a tighter LSA, this retaining some driveability. The rectangle heads need more overlap relative to duration to retain tq and still make good power compared to cathedrals. Just keep duration in the low to mid 220's and run as much compression that's safe, up to ~11.5:1 on 93.
Jason
Last edited by Camaro99SS; Nov 25, 2015 at 07:45 PM.
11 Second Club
Joined: Jul 2010
Posts: 545
Likes: 2
What is the title of this thread? Op asked about the possibility of building a Ls3. Sure he could build a 383 stroker with no problem. But if he has the funds why not do a Ls3? If its done right it can be a lethal.
Thread Starter
TECH Apprentice
Joined: Jun 2014
Posts: 305
Likes: 1
From: Houston, Texas
Good to know guys. Thanks for the input. Engine is just so expensive, that IMO, it doesnt make sense going back with something that makes 400 rwhp like my old set up. I only managed a 12.52 @ 118 on that set up with road race suspension (2.3 60', bald tires). Maybe it could have went 11's but Idk. I wanted something that is noticeably faster and more powerful. Thompson motorpsports has 383 and 376 long blocks within a couple hundred dollars of each other but the LS3 would require a conversion package, different intake, ect.
Im not looking for the cheapest, but just the most hp/$
Im not looking for the cheapest, but just the most hp/$
I think you could lose a little peak HP up top. But I also think your torque curve will stronger up into the 4500 RPM range.
So again.....you can opt for HP braggin' rights or for a quicker that has more power in the RPMs that you mostly drive the car.
KW