383 builders step in Adviced needed
Thread Starter
Melting Slicks
Joined: Jul 2004
Posts: 2,295
Likes: 14
From: Grand Sport #82
383 builders step in Adviced needed
This winter I would like to do an overhaul on my Lt4 engine.
This is my parts list. Other parts are stock LT4.
Exotic Muscle 383 bottom kit (crank, pistion, rods)
LPE 219 cam
52mm TB
Fidanza flywheel
Fuel pump (High vol)
EM Headers
AFPR
PCM tune
Would this work, or is there anything more I need to make this work.
What would power would you estimate this combo at.
This is my parts list. Other parts are stock LT4.
Exotic Muscle 383 bottom kit (crank, pistion, rods)
LPE 219 cam
52mm TB
Fidanza flywheel
Fuel pump (High vol)
EM Headers
AFPR
PCM tune
Would this work, or is there anything more I need to make this work.
What would power would you estimate this combo at.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
I'd definitely go with new heads or at the very least new valvetrain components like springs and roller rockers etc.
Heads are one of the real KEYS to power, so I'd zero in on those.
With good flowing heads, I'd look for 1.1 to 1.2 HP per cubic inch.
Jake
Heads are one of the real KEYS to power, so I'd zero in on those.
With good flowing heads, I'd look for 1.1 to 1.2 HP per cubic inch.
Jake
Last edited by JAKE; Aug 15, 2008 at 03:12 PM.
Thread Starter
Melting Slicks
Joined: Jul 2004
Posts: 2,295
Likes: 14
From: Grand Sport #82
how about intake and injectors? are stock Lt4 enough?
Team Owner
Joined: Oct 2004
Posts: 35,065
Likes: 0
From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
I thought the LT4 had pretty decent heads from the factory, is that really a worthwhile expense?
I think the cam is too small and the Throttle Body is pointless.
I think the cam is too small and the Throttle Body is pointless.
Burning Brakes
Joined: Nov 2004
Posts: 781
Likes: 0
Yes, the LT4 heads and intake (and 1.6 roller rockers) should serve him well. They could be ported, but only if a larger cam is a consideration.
As always, the appropriate springs and pushrods will be required.
Lars, what are you planning to do with the car... road racing, drag racing, or mostly street/highway driving?
And what kind of emissions/inspection concerns do you have to comply with?
That LPE 219 cam is a little old tech, more for the TPI cars. It is too small for a modded LT4, 350 or 383.
A 52mm or 58mm throttle body should stay in the mix, as should larger injectors, depending on the final combination (larger cam? ported heads? racing use?) and the capabilities of the tuner/programmer.
A decent 383 LT4 is capable of 500 +plus HP (at the crank). It should be relatively easy to reach 400 RWHP without a lot of exotic parts. You can plan on plenty of torque, regardless.
As always, the appropriate springs and pushrods will be required.
Lars, what are you planning to do with the car... road racing, drag racing, or mostly street/highway driving?
And what kind of emissions/inspection concerns do you have to comply with?
That LPE 219 cam is a little old tech, more for the TPI cars. It is too small for a modded LT4, 350 or 383.
A 52mm or 58mm throttle body should stay in the mix, as should larger injectors, depending on the final combination (larger cam? ported heads? racing use?) and the capabilities of the tuner/programmer.
A decent 383 LT4 is capable of 500 +plus HP (at the crank). It should be relatively easy to reach 400 RWHP without a lot of exotic parts. You can plan on plenty of torque, regardless.
Thread Starter
Melting Slicks
Joined: Jul 2004
Posts: 2,295
Likes: 14
From: Grand Sport #82
Yes, the LT4 heads and intake (and 1.6 roller rockers) should serve him well. They could be ported, but only if a larger cam is a consideration.
As always, the appropriate springs and pushrods will be required.
Lars, what are you planning to do with the car... road racing, drag racing, or mostly street/highway driving?
And what kind of emissions/inspection concerns do you have to comply with?
That LPE 219 cam is a little old tech, more for the TPI cars. It is too small for a modded LT4, 350 or 383.
A 52mm or 58mm throttle body should stay in the mix, as should larger injectors, depending on the final combination (larger cam? ported heads? racing use?) and the capabilities of the tuner/programmer.
A decent 383 LT4 is capable of 500 +plus HP (at the crank). It should be relatively easy to reach 400 RWHP without a lot of exotic parts. You can plan on plenty of torque, regardless.
As always, the appropriate springs and pushrods will be required.
Lars, what are you planning to do with the car... road racing, drag racing, or mostly street/highway driving?
And what kind of emissions/inspection concerns do you have to comply with?
That LPE 219 cam is a little old tech, more for the TPI cars. It is too small for a modded LT4, 350 or 383.
A 52mm or 58mm throttle body should stay in the mix, as should larger injectors, depending on the final combination (larger cam? ported heads? racing use?) and the capabilities of the tuner/programmer.
A decent 383 LT4 is capable of 500 +plus HP (at the crank). It should be relatively easy to reach 400 RWHP without a lot of exotic parts. You can plan on plenty of torque, regardless.
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Melting Slicks
Joined: Jul 2004
Posts: 2,695
Likes: 0
From: Chicago Illinois
Lars, thats a beauty of a car you have. Look at these guys and what they can do for the LT4 heads. www.advancedinduction.com. If you want a real one two punch the heads and cam are a must. With out heads IMOP youll see 375rwhp. With heads 410 to 430 rwhp. Let a pro head porter advise you on a cam you should use with your set up. Your looking at 1500 to 2000 bucks for heads and cam. Think about the opti, waterpump, timming chain, plugs, nice 8.5 red wires.
Team Owner
Joined: Oct 2004
Posts: 35,065
Likes: 0
From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
I'll be redundant. Save the $400 on the throttle body and put it somewhere else that will actually do you some good.
GM is using the 48MM stock TB on this:
http://www.sdparts.com/product/12499...eAssembly.aspx
It will be plenty for you.
GM is using the 48MM stock TB on this:
http://www.sdparts.com/product/12499...eAssembly.aspx
It will be plenty for you.
Melting Slicks
Joined: Jul 2004
Posts: 2,695
Likes: 0
From: Chicago Illinois
I'll be redundant. Save the $400 on the throttle body and put it somewhere else that will actually do you some good.
GM is using the 48MM stock TB on this:
http://www.sdparts.com/product/12499...eAssembly.aspx
It will be plenty for you.
GM is using the 48MM stock TB on this:
http://www.sdparts.com/product/12499...eAssembly.aspx
It will be plenty for you.
Team Owner
Joined: Oct 2004
Posts: 35,065
Likes: 0
From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
I am just saying if it's a budgetary issue
that $400 can be spent other places, for better results.
It's not necessary, it's nice to have.
Burning Brakes
Joined: Jul 2006
Posts: 1,080
Likes: 2
From: Pittsburgh PA
if your manifold/heads can support alot of flow, it would make sense to me to get as much in as possible. twin 48mm i think flows 700-750 cfm which is fine for most builds, but a good 58mm will do 1000cfm and i feel is necessary for big hp high rpm build
From my experience on my 383, i'm noticing a big difference going from the 650-700 cfm stock MAF sensor to my 900+cfm custom MAF sensor. So if i had a stock 48mm TB, then i'd be restricting the motor the same way
From my experience on my 383, i'm noticing a big difference going from the 650-700 cfm stock MAF sensor to my 900+cfm custom MAF sensor. So if i had a stock 48mm TB, then i'd be restricting the motor the same way
Burning Brakes
Joined: Nov 2004
Posts: 781
Likes: 0
Lars, if you enjoy road racing, but still want some decent driveability, you can certainly step UP in your cam choice.
Something like 224 intake/228-230 exhaust duration (@ .050"), around .550" lift, 112 LSA... if you leave your LT4 heads alone.
Or 228-230 intake/232-236 exhaust, closer to .600" lift, 111-112 LSA... if you want to take advantage of PORTED LT4 heads.
I recommend a 52mm TB with your stock heads, and 58mm with ported LT4s. These injected 383s like to have plenty of intake air available, especially if you are looking for useable upper RPM power/TQ (which is generally desired for road racing). For purposes of power production, you can never go too big, but driveability/idle quality and RPM/tune-ability becomes the deciding factor.
30lb to 36lb SVO injectors, depending on choices ^above^.
I like the lighter flywheel, too.
Do you know the specs and dimensions of those EM headers (I may want to 'adjust' those cam choices)?
What else do we need to address? Are we already pushing you beyond your budget?
Something like 224 intake/228-230 exhaust duration (@ .050"), around .550" lift, 112 LSA... if you leave your LT4 heads alone.
Or 228-230 intake/232-236 exhaust, closer to .600" lift, 111-112 LSA... if you want to take advantage of PORTED LT4 heads.
I recommend a 52mm TB with your stock heads, and 58mm with ported LT4s. These injected 383s like to have plenty of intake air available, especially if you are looking for useable upper RPM power/TQ (which is generally desired for road racing). For purposes of power production, you can never go too big, but driveability/idle quality and RPM/tune-ability becomes the deciding factor.
30lb to 36lb SVO injectors, depending on choices ^above^.
I like the lighter flywheel, too.
Do you know the specs and dimensions of those EM headers (I may want to 'adjust' those cam choices)?
What else do we need to address? Are we already pushing you beyond your budget?
Thread Starter
Melting Slicks
Joined: Jul 2004
Posts: 2,295
Likes: 14
From: Grand Sport #82
Lars, if you enjoy road racing, but still want some decent driveability, you can certainly step UP in your cam choice.
Something like 224 intake/228-230 exhaust duration (@ .050"), around .550" lift, 112 LSA... if you leave your LT4 heads alone.
Or 228-230 intake/232-236 exhaust, closer to .600" lift, 111-112 LSA... if you want to take advantage of PORTED LT4 heads.
I recommend a 52mm TB with your stock heads, and 58mm with ported LT4s. These injected 383s like to have plenty of intake air available, especially if you are looking for useable upper RPM power/TQ (which is generally desired for road racing). For purposes of power production, you can never go too big, but driveability/idle quality and RPM/tune-ability becomes the deciding factor.
30lb to 36lb SVO injectors, depending on choices ^above^.
I like the lighter flywheel, too.
Do you know the specs and dimensions of those EM headers (I may want to 'adjust' those cam choices)?
What else do we need to address? Are we already pushing you beyond your budget?
Something like 224 intake/228-230 exhaust duration (@ .050"), around .550" lift, 112 LSA... if you leave your LT4 heads alone.
Or 228-230 intake/232-236 exhaust, closer to .600" lift, 111-112 LSA... if you want to take advantage of PORTED LT4 heads.
I recommend a 52mm TB with your stock heads, and 58mm with ported LT4s. These injected 383s like to have plenty of intake air available, especially if you are looking for useable upper RPM power/TQ (which is generally desired for road racing). For purposes of power production, you can never go too big, but driveability/idle quality and RPM/tune-ability becomes the deciding factor.
30lb to 36lb SVO injectors, depending on choices ^above^.
I like the lighter flywheel, too.
Do you know the specs and dimensions of those EM headers (I may want to 'adjust' those cam choices)?
What else do we need to address? Are we already pushing you beyond your budget?
Sounds like you know what your talking about
I like to keep my stock heads and intake. The budget seems OK so far, I am just trying to get the complete parts list done for a build.
TH EM headers are 1 3/4
