Anyone here running a 383 LT4?
Instructor
Joined: Jan 2001
Posts: 138
Likes: 0
From: Seattle WA
Re: Anyone here running a 383 LT4? (crheinish)
I think if I was building a 383 I would skip trying to find an LT4 and just find the best condition LT1 I could get my hands on. Aside from paying a premium for the car because it's an LT4, you'll probably end up replacing all or most of the components that make an LT4 an LT4 anyway (primarily the heads). The money you save on not getting the LT4 could be used to buy better guts for your 383!
Then again, this opinion is coming from a guy who just paid a rather nice chunk of change to have SOMEONE ELSE replace his fuel pump and radiator because of lacking automotive knowledge...take it for what it's worth :lol:
Then again, this opinion is coming from a guy who just paid a rather nice chunk of change to have SOMEONE ELSE replace his fuel pump and radiator because of lacking automotive knowledge...take it for what it's worth :lol:
Team Owner
Joined: Sep 2001
Posts: 62,160
Likes: 1,733
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Re: Anyone here running a 383 LT4? (crheinish)
GlockLT4 had a 383 LT1 with LT4 Hotcam, drove it quite a bit before he wrecked it I believe, then got a real LT4.
You can run a search on his threads in Tech.
You can run a search on his threads in Tech.
Racer
Joined: Sep 2001
Posts: 396
Likes: 0
From: simi valley ca
Re: Anyone here running a 383 LT4? (crheinish)
I updated by orig 92 LT1 to a 383 LT4 w/ hotcam when i threw a rod bearing. got a good deal from scoggin dickey and decided to go w/ the lt4.
i have an auto, so the idle is a little higher( 900-950RPM ). i also have a 2800 stall converter,and 3.73 rears. runs really smooth and get around 16 mpg. it was my daily driver, before i got my wife's mustang (v6) fix.
i now used it about twice a week.
BTW, it did pass the CA smog test several months ago.
shoot me an email of you have any questions.
joel
i have an auto, so the idle is a little higher( 900-950RPM ). i also have a 2800 stall converter,and 3.73 rears. runs really smooth and get around 16 mpg. it was my daily driver, before i got my wife's mustang (v6) fix.
i now used it about twice a week.
BTW, it did pass the CA smog test several months ago.
shoot me an email of you have any questions.
joel
Pro
Joined: Apr 2002
Posts: 629
Likes: 0
From: Rutland Ma
Re: Anyone here running a 383 LT4? (Onyx)
Aside from paying a premium for the car because it's an LT4, you'll probably end up replacing all or most of the components that make an LT4 an LT4 anyway (primarily the heads). The money you save on not getting the LT4 could be used to buy better guts for your 383!
Thread Starter
Burning Brakes
Joined: Nov 2002
Posts: 1,239
Likes: 1
From: Las Vegas NV
Re: Anyone here running a 383 LT4? (qkvette)
Thanks this is the type of info I was looking for. I did not come up with much doing a search. My thoughts were to build a 383 LT1 short block then add the LT4 upgrade package with Hotcam kit along with a SLP 2400 stall torque converter and custom Ed Wright programming. I assumed this package would be good for approximately 450 gross horsepower and I planned on keeping the stock throttle body, exhaust manifolds, and 2.59 gear ratio. I am going to need an engine one day so I am trying to plan ahead. Thanx
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: Anyone here running a 383 LT4? (crheinish)
I am running a 396LT4 with a cam considerably larger than a HOT cam. It has very good street manners and can be driven daily. Its also supercharged :)
It is very docile with the 224/236 cam with over 560 lift. It still gets over 20 MPG and can be driven in stop and go traffic without over heating.
I would not even bother going to the expense of buying a "LT4" because one, you will pay a premium for it and two you can buy better aftermarket heads from AFR that will far outflow any ported LT4 OEM head and you will get a better head in the end. There are some that will say that a OEM LT4 head ported will outflow an aftermarket head, well that maybe but remember its not just big numbers that count, other factors such as flow velocity count just as much and chamber design and port roof demensions as well. You will still have to use a GM LT4 manifold so that will be an added expense.
If you want BIG HP numbers get some AFR LT4 heads with the competition CNC porting. I run AFR 200+ LT4 heads as I wanted to retain streetable port velocities, these heads will make the numbers you will want in a streetable 383 or 396.
[Modified by tjwong, 7:10 PM 6/14/2003]
It is very docile with the 224/236 cam with over 560 lift. It still gets over 20 MPG and can be driven in stop and go traffic without over heating.
I would not even bother going to the expense of buying a "LT4" because one, you will pay a premium for it and two you can buy better aftermarket heads from AFR that will far outflow any ported LT4 OEM head and you will get a better head in the end. There are some that will say that a OEM LT4 head ported will outflow an aftermarket head, well that maybe but remember its not just big numbers that count, other factors such as flow velocity count just as much and chamber design and port roof demensions as well. You will still have to use a GM LT4 manifold so that will be an added expense.
If you want BIG HP numbers get some AFR LT4 heads with the competition CNC porting. I run AFR 200+ LT4 heads as I wanted to retain streetable port velocities, these heads will make the numbers you will want in a streetable 383 or 396.
[Modified by tjwong, 7:10 PM 6/14/2003]
Le Mans Master
Joined: Sep 2000
Posts: 6,473
Likes: 1
From: Cleveland
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Re: Anyone here running a 383 LT4? (tjwong)
I am running a 396LT4 with a cam considerably larger than a HOT cam. It has very good street manners and can be driven daily. Its also supercharged :)
Back to the thread, just stick to an LT1
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Burning Brakes
Joined: Dec 2001
Posts: 901
Likes: 15
From: Punta Gorda, FL
Re: Anyone here running a 383 LT4? (crheinish)
This is a SUPER combo for a street car. I just finished a 383 built up with Hot Cam and I'm very pleased. Although I have ported LT1 heads. Either way, you won't be unhappy. You won't get to 450 hp without headers, exhaust and no cats. Enlarge TB to 52mm. You have to change the mainfolds for the LT4 heads, I believe. Definitely change the gears.
Instructor
Joined: Jan 2001
Posts: 138
Likes: 0
From: Seattle WA
Re: Anyone here running a 383 LT4? (Chefskeez6)
I would have thought that if the LT4 heads were engineered for a 350 that upping to a 383 you'd want more flow...no? Wouldn't the 383 be able to take advantage of "freer" flowing heads?
Le Mans Master
Joined: Aug 1999
Posts: 7,339
Likes: 137
From: WilkesBarre PA
Re: Anyone here running a 383 LT4? (Onyx)
Eric Fisher just built a 396 with the hot cam and ported LT4 heads and stock exhaust manifolds. So far he ran 11.55 I belive, and he said it's very streetable.
If you do go 383 or even stay with a 350 and you go to the Hot cam you will need steeper gears than the ones you have . Otherwise it will be a dog.
If you do go 383 or even stay with a 350 and you go to the Hot cam you will need steeper gears than the ones you have . Otherwise it will be a dog.
Melting Slicks
Joined: Mar 1999
Posts: 2,535
Likes: 2
From: Rochester NY
Re: Anyone here running a 383 LT4? (RichS)
Here is another one. But it not a LT4. it a 383ci LT1 with a Extreme Energy cam 222/230/@.05 .560/.603 lift
Bruce
93LT1 Conv w/ZF6
Blown D1-SC/N2O
ARE built 383ci/Stage II heads
Bruce
93LT1 Conv w/ZF6
Blown D1-SC/N2O
ARE built 383ci/Stage II heads
