C3 383
10-20-2015, 10:13 PM
#1
Heel & Toe
Thread Starter
C3 383
I built a 383: installed 202 aluminum heads, 1.5 roller rockers, .480 lift cam, headers, Edelbrock Performer EPS manifold, a 650 double pumper with vacuum secondaries, and a 700r4 transmission with a 2200 stall. It has 3.55 rear end. I expected a tremendous difference over the stock 350 engine, it is notable but not as much as I had hoped for. It seems to have more torque after it is moving, I expected more out of the hole. Should I go to a 750 carb with mechanical secondaries or what would you recommend?
Last edited by 79LewisVette33; 11-28-2015 at 10:34 AM.
10-20-2015, 10:48 PM
#3
Heel & Toe
Thread Starter
Cam is a summit .480 lift 230 duration at 05 inch lift, compression is 9.5 to 1, exhaust was changed to dual 2 1/2 diameter. Used the same mufflers which I am not happy with the sound and question the flow, will change them in the spring
Last edited by 79LewisVette33; 10-20-2015 at 11:00 PM.
10-20-2015, 10:50 PM
#4
Melting Slicks
Member Since: Apr 2009
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I would put a 600 cfm vacuum secondary carburetor on it to limit the amount of throttle opening off the line. Mechanical secondary carburetors are fine at 4000+ rpm but at lower rpm's they are too much for the engine to swallow.
10-20-2015, 10:54 PM
#5
Race Director
He's said he has a vac secondary carb and I think he means dual feed not double pumper. It can't be a vac secondary double pumper, there isn't one.
10-20-2015, 10:57 PM
#6
Race Director
To the OP. What cam? .480 lift doesn't help much. Hydraulic? Hydraulic roller? What's the Summit part#?
The Torker isn't helping your bottom end much either.
The Torker isn't helping your bottom end much either.
10-20-2015, 11:12 PM
#7
Heel & Toe
Thread Starter
You went the other way than I thought I would be advised for a 383, but thank you
10-20-2015, 11:14 PM
#8
Heel & Toe
Thread Starter
10-20-2015, 11:18 PM
#9
I built a 383: installed 202 aluminum heads, 1.5 roller rockers, .480 lift cam, headers, torker manifold, a 650 double pumper with vacuum secondaries, and a 700r4 transmission with a 2200 stall. It has 3.55 rear end. I expected a tremendous difference over the stock 350 engine, it is notable but not as much as I had hoped for. It seems to have more torque after it is moving, I expected more out of the hole. Should I go to a 750 carb with mechanical secondaries or what would you recommend?
Take the car to the track and get some 1/4 mile speed numbers so you can compare to other setup's.
eg my ZZ383 with 3.08 rear with my TH350 would be 99 MPH. With a change to a (T56 close ratio ) and the same rear I am at 104 MPH.
10-20-2015, 11:21 PM
#10
Team Owner
Member Since: Oct 2004
Location: altered state
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St. Jude Donor '05
A good dual plane and headers would wake it up. Not much of a converter for that cam thats almost stock;2200 just isnt enough
Did you curve the distributor that can make a night and day difference in power.
Sounds like he has ahyd flat tappet..
do you remember what brand and size heads they are?
Did you curve the distributor that can make a night and day difference in power.
Sounds like he has ahyd flat tappet..
do you remember what brand and size heads they are?
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96 lt-4 (10-21-2015)
10-20-2015, 11:30 PM
#11
Race Director
A good dual plane and headers would wake it up. Not much of a converter for that cam thats almost stock;2200 just isnt enough
Did you curve the distributor that can make a night and day difference in power.
Sounds like he has ahyd flat tappet..
do you remember what brand and size heads they are?
Did you curve the distributor that can make a night and day difference in power.
Sounds like he has ahyd flat tappet..
do you remember what brand and size heads they are?
I think the cam is an SUM 1784. A bit wimpy for a 383 and the 112 LSA isn't helping with the bottom end grunt either. A cam with tighter LSA, a good dual plane and headers plus a higher stall converter would help. At this point the easiest change is a decent intake. The carb he has is fine. The heads are still a mystery. Maybe he went to bed, he's a couple hours ahead of us.
10-21-2015, 05:29 AM
#12
Le Mans Master
As others have stated, the torker is going to hurt a bit over a good dual plan intake and the heads and cam are paramount to maximum power generation with superior aluminum heads and roller cams delivering significant power advantages over just any aluminum head and a flat tappet cam with modest lift, 383 or not. The .480 lift cam is only slightly better than an L-82 stock cam at .450/.460 222 duration, 114 lSA and depending on the heads is not going to offer huge power gains over the stock 350.
The problem I have noticed with many of the 383 engine builds is that unless you maximize the components such as compression, heads, and cam (roller), the power advantages over a properly built 355 are negligible and often inferior. I just read on this forum of a nice 383 build with relatively modest components making 440 Gross HP on the engine dyno and another thread about a 355 build with better heads and a moderate roller cam with more compression (10:1) making 475 Gross HP on the engine dyno and more torque.
I thought about a 383 rotating assembly for my stock L-82 when I did the rebuild but decided that keeping the stock forged crankshaft, forged rods, etc was a better option that purchasing aftermarket 383 components (Just bothers me to put a 383 in a C3 since that engine never came in a C3-just me) betting that with the JE forged racing pistons (9:1), AFR 180 64 CC aluminum heads, Howards Roller cam (.525/.525), and stock L-82 aluminum intake, I could make all the power I would need for the street. I am shocked at the power the 355 makes now....its not like my 10 Z06 but its not that FAR behind....perfect for a C3 chassis, suspension, and drivetrain. Another way to look at this dilemma is consider the power that a 427 makes versus a 454, depending on the build, the extra 27 cubes of the 454 is pretty negligible on the street.
The problem I have noticed with many of the 383 engine builds is that unless you maximize the components such as compression, heads, and cam (roller), the power advantages over a properly built 355 are negligible and often inferior. I just read on this forum of a nice 383 build with relatively modest components making 440 Gross HP on the engine dyno and another thread about a 355 build with better heads and a moderate roller cam with more compression (10:1) making 475 Gross HP on the engine dyno and more torque.
I thought about a 383 rotating assembly for my stock L-82 when I did the rebuild but decided that keeping the stock forged crankshaft, forged rods, etc was a better option that purchasing aftermarket 383 components (Just bothers me to put a 383 in a C3 since that engine never came in a C3-just me) betting that with the JE forged racing pistons (9:1), AFR 180 64 CC aluminum heads, Howards Roller cam (.525/.525), and stock L-82 aluminum intake, I could make all the power I would need for the street. I am shocked at the power the 355 makes now....its not like my 10 Z06 but its not that FAR behind....perfect for a C3 chassis, suspension, and drivetrain. Another way to look at this dilemma is consider the power that a 427 makes versus a 454, depending on the build, the extra 27 cubes of the 454 is pretty negligible on the street.
Last edited by jb78L-82; 10-21-2015 at 08:13 PM.
10-21-2015, 09:42 PM
#13
Heel & Toe
Thread Starter
Do you have any base line testing to compare. eg 1/4 mile speed numbers ?? If you are only using the "Seat of the pants sensor" you will always be disapointed.
Take the car to the track and get some 1/4 mile speed numbers so you can compare to other setup's.
eg my ZZ383 with 3.08 rear with my TH350 would be 99 MPH. With a change to a (T56 close ratio ) and the same rear I am at 104 MPH.
Take the car to the track and get some 1/4 mile speed numbers so you can compare to other setup's.
eg my ZZ383 with 3.08 rear with my TH350 would be 99 MPH. With a change to a (T56 close ratio ) and the same rear I am at 104 MPH.
10-21-2015, 09:59 PM
#14
Heel & Toe
Thread Starter
A good dual plane and headers would wake it up. Not much of a converter for that cam thats almost stock;2200 just isnt enough
Did you curve the distributor that can make a night and day difference in power.
Sounds like he has ahyd flat tappet..
do you remember what brand and size heads they are?
Did you curve the distributor that can make a night and day difference in power.
Sounds like he has ahyd flat tappet..
do you remember what brand and size heads they are?
10-21-2015, 10:01 PM
#15
Heel & Toe
Thread Starter
As others have stated, the torker is going to hurt a bit over a good dual plan intake and the heads and cam are paramount to maximum power generation with superior aluminum heads and roller cams delivering significant power advantages over just any aluminum head and a flat tappet cam with modest lift, 383 or not. The .480 lift cam is only slightly better than an L-82 stock cam at .450/.460 222 duration, 114 lSA and depending on the heads is not going to offer huge power gains over the stock 350.
The problem I have noticed with many of the 383 engine builds is that unless you maximize the components such as compression, heads, and cam (roller), the power advantages over a properly built 355 are negligible and often inferior. I just read on this forum of a nice 383 build with relatively modest components making 440 Gross HP on the engine dyno and another thread about a 355 build with better heads and a moderate roller cam with more compression (10:1) making 475 Gross HP on the engine dyno and more torque.
I thought about a 383 rotating assembly for my stock L-82 when I did the rebuild but decided that keeping the stock forged crankshaft, forged rods, etc was a better option that purchasing aftermarket 383 components (Just bothers me to put a 383 in a C3 since that engine never came in a C3-just me) betting that with the JE forged racing pistons (9:1), AFR 180 64 CC aluminum heads, Howards Roller cam (.525/.525), and stock L-82 aluminum intake, I could make all the power I would need for the street. I am shocked at the power the 355 makes now....its not like my 10 Z06 but its not that FAR behind....perfect for a C3 chassis, suspension, and drivetrain. Another way to look at this dilemma is consider the power that a 427 makes versus a 454, depending on the build, the extra 27 cubes of the 454 is pretty negligible on the street.
The problem I have noticed with many of the 383 engine builds is that unless you maximize the components such as compression, heads, and cam (roller), the power advantages over a properly built 355 are negligible and often inferior. I just read on this forum of a nice 383 build with relatively modest components making 440 Gross HP on the engine dyno and another thread about a 355 build with better heads and a moderate roller cam with more compression (10:1) making 475 Gross HP on the engine dyno and more torque.
I thought about a 383 rotating assembly for my stock L-82 when I did the rebuild but decided that keeping the stock forged crankshaft, forged rods, etc was a better option that purchasing aftermarket 383 components (Just bothers me to put a 383 in a C3 since that engine never came in a C3-just me) betting that with the JE forged racing pistons (9:1), AFR 180 64 CC aluminum heads, Howards Roller cam (.525/.525), and stock L-82 aluminum intake, I could make all the power I would need for the street. I am shocked at the power the 355 makes now....its not like my 10 Z06 but its not that FAR behind....perfect for a C3 chassis, suspension, and drivetrain. Another way to look at this dilemma is consider the power that a 427 makes versus a 454, depending on the build, the extra 27 cubes of the 454 is pretty negligible on the street.
10-21-2015, 10:08 PM
#16
Safety Car
You sound like you built a very mild 383 , that being said you need to tune it start with the distributor and timing look for pars paper on timing here on the forum ..
10-21-2015, 10:18 PM
#17
Drifting
A dual plane intake and some fine tuning should make a noticeable difference.1.6 rockers is a good upgrade most of the time.I think your money would be better spent on a different cam.
Yes headers will help everywhere but for driveability and low end switching to a dual plane intake and setting up the distributor will get you pointed in the right direction.
Yes headers will help everywhere but for driveability and low end switching to a dual plane intake and setting up the distributor will get you pointed in the right direction.
Last edited by 96 lt-4; 10-21-2015 at 10:23 PM.
The following users liked this post:
79LewisVette33 (10-21-2015)
10-21-2015, 10:26 PM
#18
Heel & Toe
Thread Starter
I think the cam is an SUM 1784. A bit wimpy for a 383 and the 112 LSA isn't helping with the bottom end grunt either. A cam with tighter LSA, a good dual plane and headers plus a higher stall converter would help. At this point the easiest change is a decent intake. The carb he has is fine. The heads are still a mystery. Maybe he went to bed, he's a couple hours ahead of us.
10-21-2015, 10:28 PM
#19
Heel & Toe
Thread Starter
It has a new HEI distributor, I tried some lighter springs, I will try changing the weights too, thank you for the help
10-21-2015, 10:44 PM
#20
Heel & Toe
Thread Starter
A dual plane intake and some fine tuning should make a noticeable difference.1.6 rockers is a good upgrade most of the time.I think your money would be better spent on a different cam.
Yes headers will help everywhere but for driveability and low end switching to a dual plane intake and setting up the distributor will get you pointed in the right direction.
Yes headers will help everywhere but for driveability and low end switching to a dual plane intake and setting up the distributor will get you pointed in the right direction.