blower carbs tuning (long) - 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> Engine
User Name
lost password?   |   register now

LinkBack Thread Tools
  #1 (permalink)  
Old 09-24-2011, 03:29 PM
Registered User
Last photo:
Join Date: Jul 2011
Location: Wentzville,MO
Posts: 190
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
blower carbs tuning (long)

Blown 496 with dual Holley 4777's. Manifold ref 6.5 PV's. I have stock carbs with quick fuel 4 corner idle blocks. .031 pvr's and 68 jets front, 80's rear. MSD6al Timing was locked at 32. Engine has always idled rough like too much timing and only smoothed out if timing is around 20 total but is really down on power. I put the advance back in the MSD so it has timing 15 idle and 32 total in at 2500. Idle at 1000rpm seems to like under 12.5 afr or it will lean to the 16's nearly die then recover when the clutch is disengaged and let off the gas. It will read same afr idle as steady cruising. Light acceleration as in passing will go in the 10's and slowly come back to what ever I set it at idle. When coasting it goes into the 11's. As I accelerate through the gears it will drop in to the 10's and rise into 11's. I can slowly open the throttle into the front jets and see it lean into 13's then the pv and jets rich it up. WOT is in the 10's. The cam is a hyd roller 114lca on 109icl. Edelbrock performer rpm heads. Blower turning 1:1. Plugs always look clean and porcelain turning light gray. I have 140lb cranking compression. It seems lazy rich off idle unloaded but drives fine. Never stumbles or spits. It just runs rough and has that trailer towing jerking except when accelerating. It does not have the power to smoke the tires at a 20mph wot. It really doesn't have much more than my blown 350 did. Idle screws out 1 turn with pcv on front carb and 1/2 turn no pcv. What am I missing here? Never had this much trouble blown or N/A in 40 years.

Reply With Quote Quick reply to this message

Recent Engine 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
tuning holley blower carbs Blown496 Engine 2 09-09-2011 08:41 PM
Tuning 2 Demon Carbs on a Hemi steve392 Engine 0 03-26-2007 01:17 PM
Tuning Holley Carbs meschnebly Engine 2 07-30-2005 08:45 AM
Tuning Dual Carbs Maverick Engine 9 10-18-2002 07:05 PM
tuning edelbrock carbs 1969cutlass Engine 2 07-31-2002 02:20 PM

All times are GMT -6. The time now is 10:09 AM.

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.