timing - Pontiac GTO Forum
User Tag List

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 11 (permalink) Old 02-22-2013, 06:26 PM Thread Starter
 
Join Date: Mar 2012
Location: long island new york
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
timing

what should the timing be stock 1970 400 ci gto automatic 350 hp
thanks
tony
tony g is offline  
Sponsored Links
Advertisement
 
post #2 of 11 (permalink) Old 02-23-2013, 06:31 AM
 
rickm's Avatar
 
Join Date: Feb 2012
Location: new york state
Posts: 633
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
9* btdc ( vacuum advance disconnected )
rickm is offline  
post #3 of 11 (permalink) Old 02-23-2013, 12:21 PM
Super Moderator
 
BearGFR's Avatar
 
Join Date: Aug 2008
Location: Springtown, TX
Posts: 5,731
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 122 Post(s)
Garage
Like rickm said, 9 degrees initial with the vacuum advance disconnected (the line plugged, engine idling at 750 rpm) are the factory specs.

I'd go a little further and ask you which heads the engine has and if there's been any "work" done (recurved distributor or aftermarket ignition, cam, etc.). For optimal performance, it's better (in my opinion, your mileage may vary) to set the "total" ignition advance at rpm (3000+) to what the engine "likes" and then let the initial timing just fall wherever it falls.

Bear

BearGFR
Springtown, TEXAS
BearGFR is offline  
 
post #4 of 11 (permalink) Old 02-23-2013, 02:06 PM Thread Starter
 
Join Date: Mar 2012
Location: long island new york
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
the heads are stock stock carb petronex replacing the points i had a little backfire in exhust and advanced the timing and it seems better im waiting for the weather to clear and take it for a ride maybe tomorow and ill repost on how its running. engine is a matching number stock 400 350 hp
thanks tony g
tony g is offline  
post #5 of 11 (permalink) Old 02-24-2013, 10:14 AM
Super Moderator
 
BearGFR's Avatar
 
Join Date: Aug 2008
Location: Springtown, TX
Posts: 5,731
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 122 Post(s)
Garage
Re: timing

"Stock" doesn't tell us much. Sorry for not being more specific. We need the casting numbers off the tops of the center exhaust ports on the heads (usually 2 characters).
If they're open chamber d-port heads from the same model year (or close) then they're usually "happy" with around 34-36 degrees total by 3000 rpm. The closed chamber heads from 67 and earlier tend to like more - as much as 38 to 40 sometimes.

Bear

BearGFR
Springtown, TEXAS
BearGFR is offline  
post #6 of 11 (permalink) Old 02-24-2013, 12:46 PM
64-67 Expert
 
geeteeohguy's Avatar
 
Join Date: Feb 2008
Location: Fresno, California
Posts: 8,470
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 98 Post(s)
If it's a stock 1970 GTO engine, I doubt very much that you'll be able to get away with 9 degrees initial timing on today's fuels. That is the spec for 100 octane fuel. You will probably have to set the base timing at about 4 degrees BTDC if that to avoid detonation.
geeteeohguy is online now  
post #7 of 11 (permalink) Old 02-24-2013, 02:33 PM Thread Starter
 
Join Date: Mar 2012
Location: long island new york
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
timing

timing mark on balancer goes from 0 to 12 tried 9 and it backfired threw exhust so i went past 12 to what might be about 16 and seems to like it no backfire i will check numbers on manifold
thanks

Last edited by tony g; 02-24-2013 at 02:55 PM.
tony g is offline  
post #8 of 11 (permalink) Old 02-24-2013, 02:34 PM Thread Starter
 
Join Date: Mar 2012
Location: long island new york
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
mean # off the heads
tony g is offline  
post #9 of 11 (permalink) Old 02-24-2013, 02:36 PM Thread Starter
 
Join Date: Mar 2012
Location: long island new york
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
heads are j079d
tony g is offline  
post #10 of 11 (permalink) Old 02-24-2013, 03:32 PM
 
rickm's Avatar
 
Join Date: Feb 2012
Location: new york state
Posts: 633
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
keep in mind, temperature, fuel octane, altitude, and the condition of the individual motor will alter timing. youl get it. i run sunoco 93 in n.y. and it seems fine.
rickm is offline  
Sponsored Links
Advertisement
 
Reply

  Pontiac GTO Forum > The 1964-1974 Pontiac Tempest, Lemans & GTO > 1964-1974 Tempest, LeMans & GTO Engine Tuning and High Performance

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Pontiac GTO Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
69-350 Timing chin 1964-1974 Tempest, LeMans & GTO Engine Tuning and High Performance 1 03-29-2011 10:10 PM
timing for 67 400 mshidner 1964-1974 Tempest, LeMans & GTO Engine Tuning and High Performance 2 09-16-2010 09:52 PM
Timing Covers and Timing Pointers ride400 1964-1974 Tempest, LeMans & GTO Technical and Electrical Wiring 8 11-24-2009 08:11 PM
? Timing On 428 goatmaster428 1964-1974 Tempest, LeMans & GTO Engine Tuning and High Performance 1 09-02-2009 12:17 PM

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

 
For the best viewing experience please update your browser to Google Chrome