Go Back   Corvette Forum > C4 Corvettes, 1984 - 1996 > C4 Tech/Performance
Sign in using an external account
Register Forgot Password?
Register Search Today's Posts Mark Forums Read FAQ Vendor Directory
Search
C4 Tech/Performance
L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Welcome to Corvetteforum.com!
Welcome to Corvetteforum.com.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join Corvetteforum.com today!


Corvette Store
 
 
C7 Parts & Accessories
C6 Parts & Accessories
C5 Parts & Accessories
C4 Parts & Accessories
C3 Parts & Accessories
C2 Parts & Accessories
C1 Parts & Accessories
Wheels & Tires
Sponsored Ads
 
 
Vendor Directory
  
Reply
 
 
 
 
Thread Tools Search this Thread
Old 01-14-2009, 06:40 PM   #1
slickfx3
CF Senior Member
 
slickfx3's Avatar
 
Member Since: Oct 2008
Location: Los Angeles CA
Default pros and cons of a 383 vs. a 396 sbc gen1 stroker

there is a debate that i would like to clarify, so any guru horsepower authorities chime in,...
slickfx3 is offline   Reply With Quote
Old 01-14-2009, 06:57 PM   #2
Demonic85
CF Senior Member
 
Demonic85's Avatar
 
Member Since: Feb 2006
Location: sw Ohio
Default

396 will cost more to build, more "meat" has to be taken off the block to get the new crank to fit. Yes it would make more HP though if built with the same kind of parts (cam, intake, heads, etc).
Demonic85 is offline   Reply With Quote
Old 01-14-2009, 07:02 PM   #3
slickfx3
CF Senior Member
 
slickfx3's Avatar
 
Member Since: Oct 2008
Location: Los Angeles CA
Default

keep it comin'
slickfx3 is offline   Reply With Quote
Old 01-14-2009, 08:30 PM   #4
neat
CF Senior Member
 
Member Since: May 2001
Location: Raleigh, NC
Send a message via AIM to neat Send a message via MSN to neat
Default

To my knowledge, no one makes a 3.875 crank that is cast, so to go 396 you must use a forged crank. If you don't plan to stay NA and keep it under 7000 RPM, in my opinion there is no need for a forged crank, so that would be a cost benefit to the 383.

Also to the best of my knowledge you must use a 5.85 rod with a 396, where you have some options for rod length with the 383.

I think the 396 will make more power, but the rod angularity and piston speed differences between it and the 383 make the 383 a better engine, IMO.
neat is offline   Reply With Quote
Old 01-14-2009, 09:14 PM   #5
slickfx3
CF Senior Member
 
slickfx3's Avatar
 
Member Since: Oct 2008
Location: Los Angeles CA
Default

Quote:
Originally Posted by neat View Post

I think the 396 will make more power, but the rod angularity and piston speed differences between it and the 383 make the 383 a better engine, IMO.
eloborate on the piston speed thing and angle please
slickfx3 is offline   Reply With Quote
Old 01-14-2009, 09:47 PM   #6
StealthLT4
CF Senior Member
Support Corvetteforum!
 
StealthLT4's Avatar
 
Member Since: Dec 2006
Location: St Marys GA
Send a message via AIM to StealthLT4
Default

Someone else may be able to elaborate better, but here's what I know:

The higher stroke means that, when the piston starts moving downward on the power stroke, the con rod is at a greater angle from vertical (wrt the piston), and therefore more of the force is put on the sidewall of the cylinder instead of down to the crank. This is a bad thing. Also, with the larger stroke, getting the same rpm will mean higher average piston speeds, which presents an engine longevity issue.

A 396 will still make more power, but may not rev as freely as a 383, and might not survive as long at the higher revs. That's only comparing 2 identical engines though; quality components will make either build work well.
StealthLT4 is offline   Reply With Quote
Old 01-14-2009, 09:50 PM   #7
slickfx3
CF Senior Member
 
slickfx3's Avatar
 
Member Since: Oct 2008
Location: Los Angeles CA
Default

so far so good, were not talkin small block fords here, okay chevy guys wadup?
slickfx3 is offline   Reply With Quote
Old 01-14-2009, 11:13 PM   #8
tpi 421 vette
CF Senior Member
 
tpi 421 vette's Avatar
 
Member Since: Mar 2002
Location: S.L.C. UT
Default

A 396 is the same stroke as a 421. You can use a 6.00" rod with a 1.062" compression height piston. So the rod ratio and angularity with that configuration isn't too bad. Like mentioned... a 396 will require a forged crank, which adds alot to the price.I would also recommend some good stroker rods. If your budget allows, I would do a 396 over a 383. You could also go a 4.00" stroke which would give you a 408.XX or a 409 as alot of people like to call them. But it takes alot of clearancing, and you can go 6.0" rod with a 1.00" piston compression height. Or use a 5.85 rod with a 1.150" compression height piston. I have done several, but a 4.0" stroke starts to really push the limits. I have also done a 4.125" stroke, but I don't know if I would recommend it after all I went thru to make it work.

I think you would be happy with a nice 396.
__________________
1991 6sp 421, miniram, AFR 220, F.A.S.T. NOS , Ford 9", Strange Ultra case, Strange 35 spline axles and spool, 4 link 9.87@141.502.3 rwhp 481.8 rwtq
With 200 shot nitrous 720.3 rwhp 790.0 rwtq.
450ci, AFR 235, MamoRam, Crane solid roller, DA corrected to sealevel thru mufflers 9.65@145.79. Pump gas motor.
464 tall deck SBC, AFR 245, Crane solid roller. DA corrected to sealevel thru mufflers 9.30@155

2008 C6, LS3,A6,3LT,Z51,NPP, Air intake, tune, underdrive pulley
tpi 421 vette is offline   Reply With Quote
Old 01-14-2009, 11:27 PM   #9
Orr89rocz
CF Senior Member
 
Member Since: Jul 2006
Location: Pittsburgh PA
Default

Go 383, especially if not needing a forged crank

difference in power is marginal, 10-15hp with same cam/heads but will lose some torque with 383.. 396 will make abit more torque and possibly abit more midrange hp but i dont think the price is worth it
Orr89rocz is offline   Reply With Quote
Old 01-14-2009, 11:40 PM   #10
slickfx3
CF Senior Member
 
slickfx3's Avatar
 
Member Since: Oct 2008
Location: Los Angeles CA
Default

Quote:
Originally Posted by Orr89rocz View Post
Go 383, especially if not needing a forged crank

difference in power is marginal, 10-15hp with same cam/heads but will lose some torque with 383.. 396 will make abit more torque and possibly abit more midrange hp but i dont think the price is worth it

hmmmm. great answer for a question i have yet to think about.

nominal increases with the same cam, is that across the board, or will a bigger cam benefit the bigger motor better than the smaller?

i know that's a tough question to answer because they would taylor the cam to use and engine size, but that is the base line question.
slickfx3 is offline   Reply With Quote
Old 01-15-2009, 12:02 AM   #11
JimiHendrix
CF Senior Member
 
Member Since: Jul 2007
Default 383 wins hands down!

I've researched this issue over a period of time. I've spoken with lLoyd Elliott of portworks, and I spoke with Andy Jensen. . . in person. . . Andy owns a machine shop in northeast PA. Both experts were in agreement that; 1) 396 will only make slightly more power than a 383 because the intake and heads cannot feed the 396 engine any more power. 2) The combustion chamber and head design severly limits the 396's ability to make much more power than the 383. Just look at the heads on a big block compared to the small block. 3) if there is any bit of core shift, you WILL grind thru to the water jacket on a 396. 4) more parts options with a 383 (especially pistons).

So, the verdict for me was: to go with a fully forged 383 with a good package. Aim for optimum cam and heads. There are a whole lot of 350s putting out more torque and hp than a typical 396. There is one guy here running a 370 that is putting out 475 rwhp!!! The secret to power in these engines. . . are in the cylinder heads

To sum it all up. 396 aint worth the extra headache. Andy told me that I will be more than surprised with a healthy 383 street machine, set up with a mild stall and 3:07 gears. He told me that if I wanted a significant 383 street machine with close to 500 rwhp, to have a sheet metal intake fabricated, high lift moderate duration solid roller cam, and install race heads.......nahhhhh. IT needs to be driveable.

Anyway, that's my take on it.
JimiHendrix is offline   Reply With Quote
Old 01-15-2009, 02:54 AM   #12
Muffin
CF Senior Member
 
Muffin's Avatar
 
Member Since: Jun 1999
Location: Merritt Ils Fl
Default

The latest issue of Chevy High Performance goes into this in detail. Confess I just scanned it cause I have all the parts and pieces for a 383.
Muffin is offline   Reply With Quote
Old 01-15-2009, 03:04 AM   #13
pologreen1
CF Senior Member
 
pologreen1's Avatar
 
Member Since: Dec 2007
Default

I would like a 396, but I also figured that a 383 is more suitable and practical for my car when I do it.
pologreen1 is offline   Reply With Quote
Old 01-15-2009, 07:21 AM   #14
mseven
CF Senior Member
 
mseven's Avatar
 
Member Since: Feb 2005
Location: The Motor City
Default

Quote:
Originally Posted by JimiHendrix View Post
1) 396 will only make slightly more power than a 383 because the intake and heads cannot feed the 396 engine any more power. 2) The combustion chamber and head design severly limits the 396's ability to make much more power than the 383. Just look at the heads on a big block compared to the small block. 3) if there is any bit of core shift, you WILL grind thru to the water jacket on a 396. .
1)what cylinder heads and intake can't feed it enough ?
2)what cylinder head design "severly limits" it to making more power ?
3)not at 396, going bigger bore may run into problems though
I have no idea what you are talking about here, but you need to keep researching. If you are talking about using a 113 head and a TPI, then ANY motor would suffer from achieving it's max. potentilal.
mseven is offline   Reply With Quote
Old 01-15-2009, 08:07 AM   #15
JimiHendrix
CF Senior Member
 
Member Since: Jul 2007
Default

Hello, we are talking gen I SM here.....am I correct?

It's pretty simple. Imagine taking a small block head and placing it on a big block engine. The cylinder head design concerns the limited valve size that you can put in a small block head, and the small combustion chamber shrouds the valves, inhibiting the volume of fuel air mixture you can put in cylinder. Even the GEN II LT1 intake is very limited as to the volume of F/A that it can feed a big block sized engine.

There comes a point where you get less of an increase of power. . . when you increase the size of the engine and change nothing else. That point of diminishing returns is at the 383 to 396 displacement change.

If it were true, you would get nearly twice the benefit from going from a 350 to a 383....vs. 350 to a 396. But, you don't even get 5% overall more power out of a 396, compared to a 383. (you get approx 4% more hp and 6% more torque). Reason: F/A intake restriction.

Show me a 396 putting out more power than AI's featured 383 NA engine getting 10 second quarter miles....."show me show me.....that you really love me.....actions speak louder than worddsssss" ahhh, that's a 80's song lyric...

Quote:
Originally Posted by mseven View Post
1)what cylinder heads and intake can't feed it enough ?
2)what cylinder head design "severly limits" it to making more power ?
3)not at 396, going bigger bore may run into problems though
I have no idea what you are talking about here, but you need to keep researching. If you are talking about using a 113 head and a TPI, then ANY motor would suffer from achieving it's max. potentilal.

Last edited by JimiHendrix; 01-15-2009 at 08:10 AM.
JimiHendrix is offline   Reply With Quote
Old 01-15-2009, 08:22 AM   #16
mseven
CF Senior Member
 
mseven's Avatar
 
Member Since: Feb 2005
Location: The Motor City
Default

Quote:
Originally Posted by JimiHendrix View Post
It's pretty simple. Imagine taking a small block head and placing it on a big block engine. The cylinder head design concerns the limited valve size that you can put in a small block head, and the small combustion chamber shrouds the valves, inhibiting the volume of fuel air mixture you can put in cylinder. The LT1 intake is very limited as to the volume of F/A that it can feed a big block sized engine. intake restriction.
Show me a 396 putting out more power than AI's featured 383 NA engine getting 10 second quarter miles....."show me show me.....that you really love me.....actions speak louder than worddsssss" ahhh, that's a 80's song lyric...
Once again, here is a fountain of misinformation. If cylinder heads were a restriction then there would not be a cylinder head available to support anything above 350ci..according to you, or at least make power. As to intakes, an LT-1 is not the only intake available on the planet. You want to make compares to a track car ?
I think your point would be better illustrated by showing all of us your motor combo, dyno sheet, et's etc.
since you like to make compares, here is a bosted 406ci...(not enough cylinder head)
http://www.youtube.com/watch?v=gQiyH-kKgRo
mseven is offline   Reply With Quote
Old 01-15-2009, 11:38 AM   #17
AKS Racing
CF Senior Member
 
AKS Racing's Avatar
 
Member Since: Apr 2001
Location: Houston TX
Default

Quote:
Originally Posted by neat View Post
...Also to the best of my knowledge you must use a 5.85 rod with a 396, where you have some options for rod length with the 383...
This is true when going to a boosted application, but on N/A you can still use the 6.000" rod in a 3.875" and a 4.000" stroke application.

Quote:
Originally Posted by JimiHendrix View Post
... 3) if there is any bit of core shift, you WILL grind thru to the water jacket on a 396. ...
This should not be an issue with the L-98 blocks. The old 400 blocks, yes, more modern blocks, no. Also, by judicious selection of components (rods, crank, etc), much of the grinding required is reduced.

Quote:
Originally Posted by tpi 421 vette View Post
A 396 is the same stroke as the (400 based) 421. You can use a 6.00" rod with a 1.062" compression height piston. So the rod ratio and angularity with that configuration isn't too bad. Like mentioned... a 396 will require a forged crank, which adds alot to the price.I would also recommend some good stroker rods. If your budget allows, I would do a 396 over a 383. You could also go a 4.00" stroke which would give you a 408.XX or a 409 as alot of people like to call them. But it takes alot of clearancing, and you can go 6.0" rod with a 1.00" piston compression height. Or use a 5.85 rod with a 1.150" compression height piston. I have done several, but a 4.0" stroke starts to really push the limits. I have also done a 4.125" stroke, but I don't know if I would recommend it after all I went thru to make it work. ...
A lot of good info above with one slight edit for clarity. I have done similar builds and experienced the same. The 421 using the 4.125" stroke in a 4.030" bore (350 based block) tends to be more trouble than it is worth. The 421, using the 400 based block (like Jim typically builds), is certainly worthwhile.

And there are plenty of heads on the market that will easily support the HP goals of these large CID type builds.
Aaron
AKS Racing is offline   Reply With Quote
Old 01-15-2009, 01:25 PM   #18
95wht6spd
CF Senior Member
 
95wht6spd's Avatar
 
Member Since: Jul 2000
Location: Greensboro NC
Default

Quote:
Originally Posted by JimiHendrix View Post
I've researched this issue over a period of time. I've spoken with lLoyd Elliott of portworks, and I spoke with Andy Jensen. . . in person. . . Andy owns a machine shop in northeast PA. Both experts were in agreement that; 1) 396 will only make slightly more power than a 383 because the intake and heads cannot feed the 396 engine any more power. 2) The combustion chamber and head design severly limits the 396's ability to make much more power than the 383. Just look at the heads on a big block compared to the small block. 3) if there is any bit of core shift, you WILL grind thru to the water jacket on a 396. 4) more parts options with a 383 (especially pistons).

So, the verdict for me was: to go with a fully forged 383 with a good package. Aim for optimum cam and heads. There are a whole lot of 350s putting out more torque and hp than a typical 396. There is one guy here running a 370 that is putting out 475 rwhp!!! The secret to power in these engines. . . are in the cylinder heads

To sum it all up. 396 aint worth the extra headache. Andy told me that I will be more than surprised with a healthy 383 street machine, set up with a mild stall and 3:07 gears. He told me that if I wanted a significant 383 street machine with close to 500 rwhp, to have a sheet metal intake fabricated, high lift moderate duration solid roller cam, and install race heads.......nahhhhh. IT needs to be driveable.

Anyway, that's my take on it.
I think Lloyd is referring to a 396 with GM LTx ported head castings, he feels they cannot provide enough CFM even at max porting for a 396. (I could be wrong, but when I spoke to him this is what I took away.)
95wht6spd is offline   Reply With Quote
Old 01-15-2009, 04:39 PM   #19
JimiHendrix
CF Senior Member
 
Member Since: Jul 2007
Default

For crying out loud....that engine is not normally aspirated. We aren't getting our points across to each other....so....leave it alone.

Ummmm, I see your point mseven. (that is.....you don't see mine....)

Quote:
Originally Posted by mseven View Post
Once again, here is a fountain of misinformation. If cylinder heads were a restriction then there would not be a cylinder head available to support anything above 350ci..according to you, or at least make power. As to intakes, an LT-1 is not the only intake available on the planet. You want to make compares to a track car ?
I think your point would be better illustrated by showing all of us your motor combo, dyno sheet, et's etc.
since you like to make compares, here is a bosted 406ci...(not enough cylinder head)
http://www.youtube.com/watch?v=gQiyH-kKgRo
JimiHendrix is offline   Reply With Quote
Old 01-15-2009, 04:53 PM   #20
tpi 421 vette
CF Senior Member
 
tpi 421 vette's Avatar
 
Member Since: Mar 2002
Location: S.L.C. UT
Default

Quote:
Originally Posted by AKS Racing View Post
This is true when going to a boosted application, but on N/A you can still use the 6.000" rod in a 3.875" and a 4.000" stroke application.



This should not be an issue with the L-98 blocks. The old 400 blocks, yes, more modern blocks, no. Also, by judicious selection of components (rods, crank, etc), much of the grinding required is reduced.



A lot of good info above with one slight edit for clarity. I have done similar builds and experienced the same. The 421 using the 4.125" stroke in a 4.030" bore (350 based block) tends to be more trouble than it is worth. The 421, using the 400 based block (like Jim typically builds), is certainly worthwhile.

And there are plenty of heads on the market that will easily support the HP goals of these large CID type builds.
Aaron
Good point Aaron. I forgot there are 2 different ways to do a 421. I was talking about the common 4.155x3.875. The other 421 is rare 4.030x4.125.
tpi 421 vette is offline   Reply With Quote
Old 01-15-2009, 04:53 PM
 
Go Back   Corvette Forum > C4 Corvettes, 1984 - 1996 > C4 Tech/Performance
Reload this Page pros and cons of a 383 vs. a 396 sbc gen1 stroker
 
 
 
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Ouch grum C6 Corvette General Discussion 10 05-03-2013 09:43 PM
t Crushinator Testing 0 10-29-2005 05:21 PM
:-) Magnet Testing 0 02-28-2005 09:26 PM
... INSANITY Drag Racing 1 01-23-2005 03:04 PM


Tags
396, block, build, combo, combonations, compression, gen1, good, height, motor, nitrous, piston, pistons, sbc, small, stroker


Thread Tools Search this Thread
Search this Thread:

Click for Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump


All times are GMT -4. The time now is 09:31 AM.


Emails & Password Backup