Will this cam have more vacuum in a 350 - 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
lost password?   |   register now

LinkBack Thread Tools
  #1 (permalink)  
Old 06-11-2007, 08:48 PM
Registered User
Last photo:
Join Date: Jan 2006
Location: NC
Posts: 201
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Will this cam have more vacuum in a 350

I rebuilt a 327 sbc, ran it for a while with a edelbrock performer cam, wanted a little more cam bought a engle ep-22, had good torque good top end but less than 10 on vacuum, Would this cam have more vacuum in the 30 over 350 i have in the nova now, car is a 73 chevy nova street car, motor has been decked in the past cant see engine I.D. on passinger side block i am running 416 305 heads 184 150 valves, port matched, thin head gaskets car runs good now, but i know it would run better with the ep-22, just need to know if it would have more vacuum? Thanks Wormy.

Reply With Quote Quick reply to this message
Sponsored Links
  #2 (permalink)  
Old 06-11-2007, 11:14 PM
DoubleVision's Avatar
Not Considered a Senior Member
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,658
Wiki Edits: 0

Thanks: 15
Thanked 60 Times in 57 Posts
I`m guessing it would have slightly more vacuum due to 27 more cubic inches. As for performance, the 305 heads small valves and not so good intake ports are killing all the benefits of the bigger cam, and especially will with more cubic inches.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 06-14-2007, 01:00 PM
F-BIRD'88's Avatar
Yada Yada Yada
Last photo:
Join Date: Oct 2005
Location: Ontario, Canada
Posts: 9,153
Wiki Edits: 0

Thanks: 5
Thanked 380 Times in 374 Posts
The manifold vacuum @ idlle will not change a lot, if at all.
If you want to maximize the available vacuum, give the motor as much initial advance as it will take at idle. As a tuning excersise to see the effect, temp remove the advance weights and springs from the distributor and lock out the mechanical advance. (two electrical tie wraps work well) Set your timing at 32-36deg BTC at idle. the timing is frozen and will not advance. readjust your carb idle speed and fuel mix screws for best idle around 900rpm. You'll find the idle quality and throttle response is much better. You'll make the most idle manifold vacuum possible.
Now when you get a chance you can remove the distributor and recurve the ignition advance curve. You have to limit the travel of the mechanical advance mechanism from 20 -24deg stock to about 12deg. Use moderate medium tension advance springs so the advance peaks out at about 3000rpm. Set your idle timing to about 22-24deg BTC. Full advance will be 36deg BTC.
Your 305 heads could really benefit from larger 1.94x 1.60" valves and porting.
if you want to maximise low/mid torque with your EP22 cam pull the timing cover and advance the cam a bit to a 104 intake C/L position.
With this aggressive ignition timing use cooler heat range non-projected tip spark plugs in your 305 heads. Champion RV8c or AC delco R42T work very well.
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:


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
Distributor Tuning and Theory - Part 1 Rick WI Engine 35 04-26-2011 12:38 AM
Vacuum adv.. underdog305 Engine 58 01-30-2007 11:19 AM
Ported Vacuum 72Orange Engine 18 08-07-2006 08:56 PM
roller cam in a '70's 350 davetc Engine 3 11-24-2005 12:15 PM
350 cam question Camaro1980 Engine 6 07-24-2005 05:35 AM

All times are GMT -6. The time now is 05:57 AM.

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.