383 Engine Build

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Dec 28, 2006 | 02:43 PM

SoCalErv

Thread Starter

Burning Brakes

Joined: Oct 2006

Posts: 1,089

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From: Native Californian CALIFORNIA

Army

383 Engine Build

I have a local builder that has suggested these specs for my car based on 3:08 rearend, TH400 tranny and stock converter.

Block - .030 over
Pistons - Speedppro Forged piston L2491F30
Heads - Dart Iron Eagle Heads - 200cc runner 2.02/1.60 valves .550 max lift part # DIE111 9.88:1 SCR
Intake - Edelbrock performer intake
Cam - Comp hydraulic cam # 12-242-2 Duration Intake 224 Exhaust 230 @.5 LS 110 Lift intake .477 Exhaust .48
Carb - stock Qjet
Exhaust - Stock

I want torque in the bottom end with a good idle basically a sleeper. Does this combo work? I do not understand DCR will this engine run on 91 unlead? What hp would you calulate this specification to yield?

Dec 28, 2006 | 03:28 PM

69vettester

Pro

Joined: Jun 2005

Posts: 725

Likes: 1

From: FL.

Whats the compression ratio?
The 200cc heads will need a bit more lift and duration. I think you should bump up the cam a notch..around, int.488 exh.502. A 383 makes better low end than a 350 with the same profile.

Also 750cfm Carb. and Headers. will match better with 200cc's.

Otherwise choose 180cc heads with less cam, and carb. Headers are always a great idea with any engine performance upgrade.
I think Its possible to end up with a dog 383 if it doesnt match up right with 200cc heads.

My 2 cents worth.
Keep us posted..

Dec 28, 2006 | 03:41 PM

SoCalErv

Thread Starter

Burning Brakes

Joined: Oct 2006

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Likes: 43

From: Native Californian CALIFORNIA

Army

The SCR is 9.88:1

Dec 28, 2006 | 04:07 PM

69vettester

Pro

Joined: Jun 2005

Posts: 725

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From: FL.

Thats good compression , but Youll be fine on 91octane still. your weak link for a real nice street Vette is that rear gear. Thats the c3 highway gear. May be easier to get your goals with 180cc heads, with that rear gear...Maybe someone else will chime in with some goods...

Dec 28, 2006 | 04:16 PM

BKbroiler

Le Mans Master

Joined: May 2002

Posts: 5,086

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From: Lebanon Township New Jersey

I had 3.08 gears and stock manifolds with full duals on my 77 with a 383 (see sig). I had a 2,500 stall converter and with that setup the car ran around 14 flat in the quarter at 100 mph. You should really consider changing the converter if you're looking for any off the line performance at all. A mild converter is OK for normal driving.

Dec 28, 2006 | 08:41 PM

SoCalErv

Thread Starter

Burning Brakes

Joined: Oct 2006

Posts: 1,089

Likes: 43

From: Native Californian CALIFORNIA

Army

Quote:

Originally Posted by BKbroiler

What exactly would raising the converter to a 2,500 stall do for me. Will it still idle? I do not understand this application

Dec 28, 2006 | 09:03 PM

1972warship

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Joined: Jan 2005

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From: Southaven MS

I am definitely not as experienced as some on this board, but if you want a smooth idle you might want to choose a cam with 112 LSA(lobe separation angle). That will also help with your 3.08 gears.

Dec 28, 2006 | 09:44 PM

BKbroiler

Le Mans Master

Joined: May 2002

Posts: 5,086

Likes: 787

From: Lebanon Township New Jersey

Quote:

Originally Posted by SoCalErv

What exactly would raising the converter to a 2,500 stall do for me. Will it still idle? I do not understand this application

By changing torque converters to one around 2,500 rpm stall speed you allow the engine to rev closer to its torque peak before the car starts to move. This gives you much improved initial acceleration, off the line. I'm talking about launching the car from a standstill whether at a traffic light or the drag strip. Even if you are not holding the car with the brakes, the converter will "flash" to a higher rpm as soon as you hit the gas.
As for idle characteristics, the higher stall converter you use, the easier it is to achieve good idle, in gear.

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Dec 28, 2006 | 10:12 PM

mbeeman350

Melting Slicks

Joined: Feb 2003

Posts: 2,529

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From: Auburndale Florida

2025 C2 of the Year ('64-'66) Finalist - Unmodified

St. Jude Donor '03-'05-'06-'07-'09

Quote:

Originally Posted by 1972warship

I am definitely not as experienced as some on this board, but if you want a smooth idle you might want to choose a cam with 112 LSA(lobe separation angle). That will also help with your 3.08 gears.

1972 Warship.. I went with the Comp Marine Roller, like the XR276 but has a 112 LSA same money at Summit, much cheaper than a custom grind! Should ship this week and have the motor back together next week

This is for my 383 build up, 2500 stall, 9.7 SCR, 190 cc alum heads, TH400 and 308 gears
Best of luck, Mark

Dec 28, 2006 | 10:22 PM

#10

1972warship

Pro

Joined: Jan 2005

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From: Southaven MS

Quote:

Originally Posted by mbeeman350

Glad to hear it. That cam is definitely one I have thought about for me as well...let me know how it goes,(also interested in the vacuum from it).

Dec 28, 2006 | 10:30 PM

#11

Frank O'Hara

Instructor

Joined: Sep 2004

Posts: 182

Likes: 0

From: Brentwood TN

Here's my 383 - idles like stock yet has unreal torque.
- Eagle Street And Strip Rotating Assembly Speed Pro 5.7 Rods with Hypereutectic Pistons w/Teflon Coated Skirts – 9.0:1 compression
Block Prep - Thermal Cleaned,Shot Blasted,Magnafluxed,Bored & Honed .030" over with Torque plates,Square Decked,Align Bored & Honed,Clearanced for Stroker Crank,Balanced.
- Cam - Comp Cams XE256H-10
Gross Valve Lift .447/.454
Duration At 0.006 Tappet Lift 256/268
- Comp Cams Pro Magnum Rocker Arms 1.52

http://73corvetteproject.blogspot.com/

Dec 29, 2006 | 09:35 AM

#12

SoCalErv

Thread Starter

Burning Brakes

Joined: Oct 2006

Posts: 1,089

Likes: 43

From: Native Californian CALIFORNIA

Army

Quote:

Originally Posted by Frank O'Hara

http://73corvetteproject.blogspot.com/

What tranny and rearend on you running. Do you have enough vacuum to operate efficiently? Stall on your TC? What heads?

Dec 29, 2006 | 09:55 AM

#13

Frank O'Hara

Instructor

Joined: Sep 2004

Posts: 182

Likes: 0

From: Brentwood TN

Quote:

Originally Posted by SoCalErv

What tranny and rearend on you running. Do you have enough vacuum to operate efficiently? Stall on your TC? What heads?

I have a M21 4 spd with 3.70 gears out back... The heads are the stock L82 heads from 73 Casting No 330545 (cast iron) 2.02/1.6" Valves, 76.18cc, tapered spark plug, screw in studs & guide plates with 76cc Combustion Chambers. The heads were pocket ported and gasket matched

The vacuum is fine the car idles at 550 rpms - with just a slight lope

Dec 29, 2006 | 10:30 AM

#14

gkull

Team Owner

Joined: Apr 1999

Posts: 21,953

Likes: 1,445

From: Reno Nevada

2024 C3 of the Year Finalist- Modified

Quote:

Originally Posted by SoCalErv

Comp Cams has just too many flat cams to be a coincidence. I used the the Crane power max 278 for years with the high intesity lifters with 1.6 roller tips.

Buy a real manifold that does give performance. The Weiand Stealth.

The Performer or lack there of is only good on pickup trucks turning lower rpm - It would really choke a 355 ci. during dyno testing it shut my motor down just over 5000 rpm with a 600 carb. At first i thought it was the carb so I installed a 750 cfm. The Performer sut it down again. the runners are just to small.

Last edited by gkull; Dec 29, 2006 at 05:48 PM.

Dec 29, 2006 | 01:27 PM

#15

SoCalErv

Thread Starter

Burning Brakes

Joined: Oct 2006

Posts: 1,089

Likes: 43

From: Native Californian CALIFORNIA

Army

Quote:

Originally Posted by Frank O'Hara

Did you ever put this on a dyno. Interested what hp and torque it produced.

Dec 29, 2006 | 05:10 PM

#16

Frank O'Hara

Instructor

Joined: Sep 2004

Posts: 182

Likes: 0

From: Brentwood TN

Quote:

Originally Posted by SoCalErv

Did you ever put this on a dyno. Interested what hp and torque it produced.

No – but I did use Engine Analyzer 3.3 (desktop engine dyno software) to model it. Results were 382HP at 5000 RPM with 433 ft lb torque at 4000 RPM

Dec 29, 2006 | 05:23 PM

#17

SoCalErv

Thread Starter

Burning Brakes

Joined: Oct 2006

Posts: 1,089

Likes: 43

From: Native Californian CALIFORNIA

Army

Quote:

Originally Posted by Frank O'Hara

No – but I did use Engine Analyzer 3.3 (desktop engine dyno software) to model it. Results were 382HP at 5000 RPM with 433 ft lb torque at 4000 RPM

since you have analyzer 3.3 what changes to your base model could be made to hit 400+hp. Would aluminum heads, etc get you there?

Dec 29, 2006 | 05:57 PM

#18

Frank O'Hara

Instructor

Joined: Sep 2004

Posts: 182

Likes: 0

From: Brentwood TN

Quote:

Originally Posted by SoCalErv

since you have analyzer 3.3 what changes to your base model could be made to hit 400+hp. Would aluminum heads, etc get you there?

I only downloaded the demo version to make the run without buying a licence

Dec 29, 2006 | 07:21 PM

#19

SoCalErv

Thread Starter

Burning Brakes

Joined: Oct 2006

Posts: 1,089

Likes: 43

From: Native Californian CALIFORNIA

Army

Quote:

Originally Posted by Frank O'Hara

I only downloaded the demo version to make the run without buying a licence

Sneaky -- I LIKE IT!!!!!!!!!

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