How much fuel pressure for a Holley 650? - Hot Rod Forum : Hotrodders Bulletin Board -- Hot Rod Forum

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

LinkBack Thread Tools
  #1 (permalink)  
Old 04-24-2011, 01:19 PM
Join Date: Aug 2004
Location: Kentucky
Age: 47
Posts: 288
Wiki Edits: 0

Thanks: 28
Thanked 4 Times in 4 Posts
How much fuel pressure for a Holley 650?

I have a 402 big block in my 57 Chevy. I had to install a Summit Racing mechanical fuel pump that has the adjustable lower housing. I needed that so I could have my fuel lines routed correctly.

The fuel pump says it puts out 5.7-8.0 psi. That is a descent range and there is no adjustment that I know of on the pump. I'm running a 650 Holley double pumper and it seems to run rich at wide open throttle. It almost bogs like it's dumping in to much fuel. I'm not sure if I should start tuning on the carb or get a fuel pressure regulator and make sure the pressure isn't too high. 8.0psi sounds kind of high, not sure if my pump is putting that much out or the lower 5.7psi.

The float levels are set right and the carb doesn't seem to be overflowing with excess fuel.

Thanks for your help!


Reply With Quote Quick reply to this message
Sponsored Links
  #2 (permalink)  
Old 04-24-2011, 01:25 PM
eloc431962's Avatar
Evil Wicked Mean And Nasty
Last wiki edit: Pilot bearing and bushings
Last journal entry: roof repair
Join Date: Nov 2008
Location: back in the garage.
Posts: 13,764
Wiki Edits: 37

Thanks: 50
Thanked 32 Times in 27 Posts
I would add the regulator if it was me, You only need 5 psi to run that's alot of engine might take alittle more but it shouldn't need 8 psi.JMO
Add the regulator and set the psi at the minimum if it. 5.7 try that or maybe 6 psi and see how it does from there you will probably still have to do some adjusting at the carb air/fuel mix to get everything right. JMO

Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 04-24-2011, 02:58 PM
327NUT's Avatar
Registered User
Join Date: Dec 2004
Location: So. Utah
Age: 73
Posts: 3,518
Wiki Edits: 0

Thanks: 2
Thanked 161 Times in 140 Posts
X2......most street Holleys are way over fuel pressured and blow the needle off the seat. Unless you run around town at 6,000 rpm all the time then 5 psi should work.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 04-24-2011, 05:42 PM
Join Date: Aug 2004
Location: Kentucky
Age: 47
Posts: 288
Wiki Edits: 0

Thanks: 28
Thanked 4 Times in 4 Posts
Thanks for the replies.

I was thinking 8 psi sounded too high. It looks like a new regulator is on my list. Some of the regulators I looked at don't have a gauge that tells how much pressure you have. The $25 units from Holley have a plug that you screw in. I guess one way is the maximum pressure and back the other way is minimum pressure.

Thanks for your time
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)


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
fuel pressure problem - holley blue pump & reg stratt134 Engine 19 04-12-2013 03:44 PM
Holley 12-803 fuel pressure regulator conversion to a bypass type? kyyx Engine 3 02-14-2010 08:29 AM
holley fuel pressure regulator syclone Engine 1 02-07-2006 08:05 PM
Holley Safety Fuel Pressure Switch Wiring camaro80 Electrical 4 01-20-2006 10:02 PM
Holley fuel pressure regulator lluciano77 Engine 2 10-11-2003 10:51 PM

All times are GMT -6. The time now is 12:45 PM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, 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 © 2020 DragonByte Technologies Ltd.
Copyright 1999 - 2012. All Rights Reserved.