newbie here building a 327 looking for atleast 400 hp. - Page 2 - Hot Rod Forum : Hotrodders Bulletin Board -- Hot Rod Forum

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

LinkBack Thread Tools
  #16 (permalink)  
Old 08-26-2012, 01:34 PM
Registered User
Last photo:
Join Date: Apr 2012
Posts: 192
Wiki Edits: 0

Thanks: 1
Thanked 23 Times in 22 Posts
Originally Posted by vinniekq2 View Post
toddalin said,,,and a dynojet dyno usually reads lower than a mustang chasis dyno. 12.8-12.9 af is great for the street.It would make more power with open exhaust and a little richer. so lets say your engine is 400 ish hp. for sure a good guideline to build 400 hp. My favourite carb for small v-8s like 327s is a 4777 with 4781 base plate and a few tweek
s like replaceable air bleeds and minor contouring etc.

Its a great share offering your parts list and actual dyno figures.
In this other set of dyno runs that include A/F ratios, in every case the leaner pull made more power at any point on the RPM band. That's why I went 1 jet leaner on the secondaries.

Initially I tried 2 jets leaner on the primaries, but that created a lean surge while cruising. I returned the primary jets and it cleared right up, so took 1 jet size from the secondaries. Taking it from the secondaries also "squares up" the mixture better as it enters the manifold.

Also, this clearly illustrates that the "bog" is created by an over-rich condition (note that the A/F drops to ~10:1 at the point of bog), rather than a lean spot as most infer. The PO of the carb was trying to chase the bog and, based on conventional wisdom, put in the 28 squirter in the secondaries. The 25 in the primaries is standard. When I changed to the 21s the bog went away, though I've not done another dyno run to see where the A/F now is at this point. But the SOP, says much improved. Note how smooth the A/F ratio is past this point.

I recognize that the dyno is NOT THE STREET and most jet a bit richer for the street to account for unknown variables and load factors that come into play. But, my A/F ratio is still safe, and a slightly leaner mixture also typically improves gas mileage and throttle response.

Reply With Quote Quick reply to this message
The Following User Says Thank You to toddalin For This Useful Post:
rock_dog (08-26-2012)
Sponsored Links
  #17 (permalink)  
Old 08-26-2012, 02:10 PM
Registered User
Last photo:
Join Date: Jan 2011
Location: Hopewell, Va
Age: 65
Posts: 1,684
Wiki Edits: 0

Thanks: 1
Thanked 192 Times in 179 Posts
newbie here building a 327 looking for atleast 400 hp.....HELP!!!!

Rock_Dog, Start out with a 327 block bored .030, decked to 9.005. Your crank cleaned and polished. 5.7 rods reconditioned or new I-Beam rods, flat top pistons IC792 are forged, KB100 are Hypereutectic. Your compression ratio with 64cc chamber heads IC792 is 9.8, with KB100 is 9.6. Choose one of these cams 12-676-4, XS268S, 1600-6000, .488/.501 lift and 230/236 duration @ .050 110 LSA or 12-220-5, 270S-8, 2000-6000.495/.495, 235/242 duration @ .050, 110 LSA. Edelbrock Performer RPM intake and a Holley or Demon 750 DP. HP should be from 425 @ 6000 rpm w/XS268S, 433 @ 6500 rpm w/270S-8. Torque 420 @ 4500 w/XS268S, 414 @ 4500 w/270S-8. With the block being decked use a Fel Pro .039-.041 head gasket to net 44-46 Quench. See toddalin's build sheet for how to finish setup.
Reply With Quote Quick reply to this message
The Following User Says Thank You to cdminter59 For This Useful Post:
rock_dog (08-26-2012)
  #18 (permalink)  
Old 08-29-2012, 08:42 PM
rock_dog's Avatar
Dumb newbie!
Join Date: Jul 2012
Location: Springfield Mo
Posts: 14
Wiki Edits: 0

Thanks: 8
Thanked 0 Times in 0 Posts
Thanks so much cdminter59! thats the kind of lay out i was looking for!
Reply With Quote Quick reply to this message

Recent Hotrodding Basics posts with photos

Quick Reply

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:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Please select your insurance company (Optional)


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
I have a 350 crate engine i want to make atleast 400 hp. chevydragster83 Engine 36 08-26-2012 12:47 PM
Building a 327, need some pointers Bad66 Engine 8 03-25-2011 12:01 PM
building a 327 alleeclan Engine 4 05-24-2010 07:42 PM
Building a 327 I really am.. Slowly chevy350_Camd Engine 2 05-15-2008 06:46 AM
Building a 283 into a 302 or 327 trbomike Engine 7 10-20-2006 03:25 PM

All times are GMT -6. The time now is 05:21 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999 - 2012. All Rights Reserved.