Tunnel Ram Questions - 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 07-06-2013, 12:12 PM
Resident Racer
Last photo:
Join Date: Feb 2013
Posts: 58
Wiki Edits: 0

Thanks: 34
Thanked 9 Times in 8 Posts
Tunnel Ram Questions

I sent this PM to PJ (painted_jester) a week ago and he asked me to put this up on the forum for everyone else to see. Feel free to chime in, guys. I'm always looking to learn more from the guys who've been there and done that!

Little background on my build.

350 SBC bored .060 over
10:1 compression
Mallory distributor with the magnetic pick up, no mechanical or vacuum advance
Double hump heads with the big 2.02 valves, ported and polished for better flow
1 5/8 inch headers
MSD 6A ignition box
Weiand 1984 tunnel ram intake port matched
1.6 ratio rockers
Summit Racing Camshaft, Hydraulic Flat Tappet, Advertised Duration 313/328, Lift .508/.533

All on a 1968 Chevy Camaro RS

I've been wanting to change out to a solid roller cam in the future and AFR 210cc aluminum heads but that's still months away.

Originally Posted by painted jester
Originally Posted by GoFastStripes
Hey PJ, I know you're the tunnel ram guru on the board so I sent ya a PM instead of posting a new thread on the hotrodding subforum.

I posted a question a few months ago and you commented on how my Holley 450s were killing the performance of my tunnel ram. I used to run twin Holley 600s in place of them but I kept fouling my plugs even when I ran hot plugs.

If I put the 600s back, do you think I should put in smaller jets? I have 54s on my 450s (same as the 600s I had) right now and I'm running slightly rich, so what do you think I should do?

The 600s have vacuum secondaries, and the 450s are mechanical. Won't cylinders 3, 4, 7 and 8 run lean if I don't use mechanical secondaries?


I am not the tunnel ram guru LOL! FBird and a few others are in the same category and answer T ram questions the same (as I do).

Yes, The vacuum secondary's, cause lean conditions on a tunnel, till Rpm and fully open throttles and equall fuel and air flow are met the center squatters are the best for equal distribution. Jets are not the only thing that fouls out plugs, you may have unmatched power valves or need to remove and plug the power valves and and step up your jetting! High Resistance wires and plugs will kill your spark intensity run non resistor plugs and try to find low resistance wires I run 40 0r 20 Ohm per foot wires, the choke towers on the carbs effect air flow and cause gas puddling in the intake at street idle speeds idle! the PCV needs to be T'ed to both carbs! or plumbed to the intake plenum right in the center of the carbs so it is equalised to the runners! or install a pump or other type crank case evacuation system. Ignition timing and idle speed also effect fuel mixture, and low compression engines and high octane fuel will fowl plugs! The altitude in areas of the country and air temp will effect jetting ( one size jets when temp is cool in the morning or evening and a jet change in the afternoon as the air temp gets hotter) 450s are good for a street small block and around 600s up for a street big block, but at the drag strip or street racing much bigger carbs are needed because of the ram effect of the high ram intakes and tuned long tube headers with at least 18 inch collectors for scavenging and exhaust velocity!!! If the exhaust is slow and restrictive you will fowl plugs quick!

Please put this on a tread My eyes are bad and I have a hard time seeing and I am not on here much in the summer months and the info is needed by other members and guests. Copy this PM and past it on a new thread! and I know FBird and others can help add to this! You need to track tune or find a safe place to test and tune in real world conditions A Dino tune helps get you close but its in controlled conditions so on the street or track its not conclusive!!!


Reply With Quote Quick reply to this message
Sponsored Links
  #2 (permalink)  
Old 07-06-2013, 06:19 PM
vinniekq2's Avatar
Registered User
Join Date: Jun 2012
Location: BC,Canada
Age: 59
Posts: 11,638
Wiki Edits: 0

Thanks: 693
Thanked 1,340 Times in 1,243 Posts
Chris is a great member and always helps when he has time. So thanks for posting and thanks to Chris for his efforts
Reply With Quote Quick reply to this message
The Following User Says Thank You to vinniekq2 For This Useful Post:
GoFastStripes (07-08-2013)
  #3 (permalink)  
Old 07-07-2013, 04:03 PM
JeffB's Avatar
Registered User
Last photo:
Join Date: Jul 2006
Location: Phoenix,AZ
Age: 71
Posts: 2,258
Wiki Edits: 0

Thanks: 21
Thanked 205 Times in 179 Posts
Based on the cubic inches and the heads and compression that you used in your build your choice of cam is hurting you with excessive duration. I would swap it out for this:http://www.summitracing.com/parts/hr...make/chevrolet The vacuum secondary 600's will work as they will regulate the CFM's that your engine demands, you will want to use Holley's trick spring pack to find the sweet spot and try a 25 or 35 power valve in them.
Reply With Quote Quick reply to this message
The Following User Says Thank You to JeffB For This Useful Post:
GoFastStripes (07-08-2013)

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
Tunnel Ram 1bay95west0 Engine 2 04-04-2011 04:10 PM
sbf hi ram tunnel ram 72fordlb Engine 9 04-13-2009 04:15 PM
Tunnel ram questions......... STATUTORY GRAPE Engine 10 08-21-2008 01:53 PM
setting tunnel ram up questions pal Engine 4 02-27-2007 04:48 PM
Tunnel ram? HemmiGremmie Engine 5 09-02-2003 05:40 PM

All times are GMT -6. The time now is 08:17 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 Hotrodders.com 1999 - 2012. All Rights Reserved.