compression for street 383 question?? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 02-04-2013, 08:52 PM
Registered User
 
Last photo:
Join Date: Jan 2013
Location: dallas texas
Posts: 196
Wiki Edits: 0

Thanks: 79
Thanked 3 Times in 3 Posts
compression for street 383 question??

Can someone tell me if i run this bottom end kit Scat Engine Rotating Assemblies 1-40805-1 - SummitRacing.com and used 70cc chamber edelbrock performer rpm heads for my 383 chevy, will it be street usable? I want to be below 10.1 compression.... Thanx

Now i got a email from Summitracing and they said using these pistons with the 64cc head...
"Based on a .025" deck and a .040" thick head gasket the compression ratio will be about 10.47:1. Pump gas may not make it. If a Zero deck block the compression moves to 11.11:1.

AC"

So im thinking if i went to a 70cc it should put me at 9.5 to 10.1 ...

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 02-04-2013, 09:02 PM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 8,062
Wiki Edits: 0

Thanks: 322
Thanked 783 Times in 749 Posts
10 or less is safe.depends on camshaft profile etc.
match the parts to the power you want/need,not what is available inone suppliers catalogue
Reply With Quote Quick reply to this message
The Following User Says Thank You to vinniekq2 For This Useful Post:
demarques_191 (02-04-2013)
  #3 (permalink)  
Old 02-04-2013, 09:14 PM
Registered User
 
Last photo:
Join Date: Jan 2013
Location: dallas texas
Posts: 196
Wiki Edits: 0

Thanks: 79
Thanked 3 Times in 3 Posts
i can always count on the homie for his strong and accurate advice!!! And your right, all im trying to do is find a kit that consist of a forged crank, i beam rods and 9.5 pistons and rings for it... ive even seen the eagle 4140 forged crank... found one online for 400.00.. but only thing is i have to coordinate my parts together
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 02-04-2013, 09:55 PM
1Gary's Avatar
Registered User
 

Last journal entry: 383 dyno sym
Last photo:
Join Date: Oct 2010
Location: Roch,NY
Age: 67
Posts: 1,538
Wiki Edits: 0

Thanks: 201
Thanked 156 Times in 142 Posts
Vinnie or for that matter,anyone else is going to tell you the same thing.Using SCR formulas you should big picture game plan a build of the stacked parts.

Real general rule of thumb is iron heads limit it to 9.5 and aluminum heads just shy of that by a point.

Understand chamber design matters vs piston design.Being down .025 in the hole isn't where I would want it.And with all this,there isn't any 87 or 89 gas to come into play.


Wallace Racing - Automotive Calculators

You being in the game now should get used to figuring out your own SCR's and DCR's. Just run what you figured out back passed us before you buy.
Reply With Quote Quick reply to this message
The Following User Says Thank You to 1Gary For This Useful Post:
demarques_191 (02-04-2013)
  #5 (permalink)  
Old 02-04-2013, 11:56 PM
68NovaSS's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Working with chromed bolts
Last journal entry: New to me T-Bucket
Last photo:
Join Date: Sep 2002
Location: Nine Mile Falls/Suncrest, WA
Posts: 5,248
Wiki Edits: 9

Thanks: 105
Thanked 133 Times in 124 Posts
Keep in mind there are no "9.5" pistons", any piston that results in a 9.5:1 c.r. is a piston with a particular top design, dished, domed, flat, and the sum of other parts, bore, combustion chamber volume, deck height, head gasket thickness, etc. So consider all factors in the equation before you fall victim to what some manufacturer or seller might call a xx.x:1 c.r. piston.
__________________
Boost adds dignity to what would otherwise be a vulgar brawl...

Midnight Sun Street Rod Association
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 02-05-2013, 12:33 AM
Registered User
 
Join Date: Aug 2012
Posts: 50
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
If this helps you any, I'm running a "true" 10.4 compression in my 406 with "IRON" heads, My cranking pressure is 210-215, it runs great on pump 91 premium, The cam is not that big either, 224/234 @50 on a 112 LSA, Your cam will be your limiting factor when it comes to compression & pump gas, You CAN run 11.1 on pump gas with aluminum heads, its done all the time, You don't necessarily need a big can neither, just stay on one with a larger LSA, like a 112-114, If your going to run an aluminum head, shoot for a solid 10.5 compression & you will be fine.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 02-05-2013, 07:17 PM
Registered User
 
Last photo:
Join Date: Mar 2007
Location: Corinth, MS
Posts: 607
Wiki Edits: 0

Thanks: 0
Thanked 30 Times in 29 Posts
demarques_191,
On an earlier thread you mentioned using 64cc heads,5.7 rods, with a 5cc flat top piston, and I said it would give you over 11:1 CR.
The kit your refering to now(1-40805-1) has 6" rods and pistons with a dish/2 valve reliefs and specs at 19.6cc volume. I come up with a CR of 9.03:1 if the piston is .025" in the hole with a 64cc head. I get 8.5:1 CR if I switch to 70cc head.
If you haven't got either one yet(heads or rotating assy) you might want to look at a kit 1-40755B1(2 piece RMS,forged crank, the good 6" rods w/7/16" bolts, forged pistons w/5cc flat tops. bearings, and internally balanced from SCAT) and buy heads with 70cc chamber to get 9.8:1 CR with .040" gasket and pistons .025" in the hole. Pretty much what I'm doingexcept I had to bore out to .040" over instead of 4.030". Kit 1-40755-1 comes without bearings and is unbalanced. Just a thought.
ssmonty
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 02-06-2013, 02:33 AM
1Gary's Avatar
Registered User
 

Last journal entry: 383 dyno sym
Last photo:
Join Date: Oct 2010
Location: Roch,NY
Age: 67
Posts: 1,538
Wiki Edits: 0

Thanks: 201
Thanked 156 Times in 142 Posts
Edit:
When I made the statement of iron heads and aluminum heads,what I meant to say was the SCR on aluminum heads should be just shy of 10.5 or more like 10.0.But in that range of 10.0 to 10.5.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 02-06-2013, 07:09 AM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
I was looking for a cam that was used in a dyno test and ran across this: How To Build A Kick-***, Pump-Gas, NPAA 680HP Small-Block Chevy - Car Craft Magazine

I do not intend to start another war about SCR vs. DCR. But this tends to support, at least in part, the idea that even nearing the extreme ends of the spectrum that more cam and more compression can run on pump gas. The engine is a big sbc, made 680 hp from about 440 ci (equivalent to a 355 making about 550 hp). Compression is 11.4:1 w/34 degrees total timing. AFR aluminum big port (245cc) heads.

To be honest, had this come up elsewhere, my opinion would have been to not run it on pump gasoline. They don't say what pump gas was used, but presumably it wasn't some ringer 100 octane race gas from a pump. And if it WAS, they need to have their *** kicked.
Reply With Quote Quick reply to this message
The Following User Says Thank You to cobalt327 For This Useful Post:
vinniekq2 (02-06-2013)
  #10 (permalink)  
Old 02-06-2013, 07:20 AM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 8,062
Wiki Edits: 0

Thanks: 322
Thanked 783 Times in 749 Posts
pump gas

Quote:
Originally Posted by cobalt327 View Post
I was looking for a cam that was used in a dyno test and ran across this: How To Build A Kick-***, Pump-Gas, NPAA 680HP Small-Block Chevy - Car Craft Magazine

I do not intend to start another war about SCR vs. DCR. But this tends to support, at least in part, the idea that even nearing the extreme ends of the spectrum that more cam and more compression can run on pump gas. The engine is a big sbc, made 680 hp from about 440 ci (equivalent to a 355 making about 550 hp). Compression is 11.4:1 w/34 degrees total timing. AFR aluminum big port (245cc) heads.

To be honest, had this come up elsewhere, my opinion would have been to not run it on pump gasoline. They don't say what pump gas was used, but presumably it wasn't some ringer 100 octane race gas from a pump. And if it WAS, they need to have their *** kicked.
sounds familiar,my 434 uses 10.75 SCR,Dart 227 heads with porting,runs on pump gas.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
195 PSI 10.3 to 1 compression on street fuel tuff82 Engine 2 08-07-2010 11:21 AM
street big block compression boatanchors Engine 4 11-17-2008 09:33 AM
Compression on street tunnel ram 383 Engine 11 11-25-2007 12:27 AM
Highest Compression For The Street boss350 Engine 23 05-27-2005 02:54 PM
compression on my 383 dk01_99 Engine 5 02-19-2003 09:05 PM


All times are GMT -6. The time now is 06:31 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.