Pontiac engine question - 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
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 11-17-2010, 02:32 PM
Registered User
 
Join Date: Nov 2010
Location: oregon
Posts: 1
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Pontiac engine question

i just got a 72 pontiac lemans 350, if i put 326 heads on it would it work? and would it increase compresion? would i have to run high octaine fuel to run it? any feedback please....

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 11-17-2010, 03:02 PM
eloc431962's Avatar
Evil Wicked Mean And Nasty
 
Last wiki edit: Pilot bearing and bushings
Last journal entry: roof repair
Last photo:
Join Date: Nov 2008
Location: back in the garage.
Posts: 13,762
Wiki Edits: 37

Thanks: 50
Thanked 28 Times in 24 Posts
When Bill see's this he can help you out. (WDCreech) ponitac man knows his stuff. Or someone else might stroll by and know about this.


Cole
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 11-17-2010, 04:25 PM
68NovaSS's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Working with chromed bolts
Last journal entry: New to me T-Bucket
Last photo:
Join Date: Sep 2002
Location: Nine Mile Falls/Suncrest, WA
Posts: 5,247
Wiki Edits: 9

Thanks: 104
Thanked 133 Times in 124 Posts
Changed the thread title, added Pontiac, making it more specific.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 11-17-2010, 04:44 PM
LATECH's Avatar
Hotrodders.com Moderator
 

Last journal entry: Motor - vator
Last photo:
Join Date: Jul 2010
Location: Northeast Pennsylvania
Posts: 5,229
Wiki Edits: 0

Thanks: 209
Thanked 259 Times in 241 Posts
I have a 350 poncho that I have a set of closed chambered heads for. It runs pretty good now but I am considering doing something similsr to your Idea. I have some closed chambered heads (i havent CC ed them yet) that I was looking to run but they would put the compression ratio over 10.25 / 1.00 to much for pump gas. I am toying with having them cnc machined to a larger chamber size but with a specific shape in mind for flame propagation to increase burn speed with out having to much compression for pump gas. There is plenty of metal to remove for changing the shape to a heart or kidney shaped chamber and to also unshroud the valves wich I have heard is a problem with the 350 pontiac due to the bore size. ( Small). This creates a problem when going to larger valves as it makes the problem worse and then you have to chamfer the top of the cylinder to gain clearance. (Difficult and tedious)
With the 326 heads that would not pose a problem as the valves are smaller and would be less shrouded by the cylinder and the chamber.
Some port work may be beneficial . I would not do any to the ports them selves ( except for a deburr of the entry and runner) but would focus on opening up the "Bowl" behind the valve as to increase the airflow in that area.
That would probably gain more than bigger valves anyway, In my opinion.
One thing I have found also is pontiac exhaust ports are smaller than intake ports, at least more so than an average engine.Pontiac uses a dual pattern camshaft design ,the exhaust duration is longer than the intake duration. Check out camshafts for pontiacs, you will see, and that is why.
CNC machining can be pricey you can dump a buttload of cash in a set of heads, probably as much as a set of aluminum performance heads from what I hear, so spend some time thinking it over.You might want to read up on porting and C C ing chambers and such so you can do it yourself and save bucks. Maybe get a cracked head at a machine shop to practice on a little first and get a known race guy to critique it for you to get the Idea and a feel for whats happening.
By the way 65 heads and up will fit ,64 and back have a different bolt pattern for the intake,and I think that 72 and up may be different also. The difference in the 64 back is the bolt pattern, 72 and up is a different exhaust crossover and would be a big exhaust leak on a 71 and back head. I think that is an accurate quote.check that out also, it could be a problem for you as well.

Last edited by latech; 11-17-2010 at 04:50 PM.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 11-17-2010, 05:05 PM
WDCreech's Avatar
Grumpy Old Goat Herder
 
Last photo:
Join Date: Apr 2006
Location: Anchorage, Alaska
Age: 70
Posts: 1,319
Wiki Edits: 0

Thanks: 3
Thanked 29 Times in 27 Posts
latech has it pretty well covered, but you didn't say which 326 heads you had or from what year 326. If they are '66 094 or '67 140s, you should be good to go. If you have '66 095 or '67 141s your compression will be to high for pump gas. Don't increase the valve lift to over about .450" because the notches in the pistons are slightly different than were the ones in '72.

Bill
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

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:
If you do not want to register, fill this field only and the name will be used as user name for your post.
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:

Log-in

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
acceleration flat spot in carb. corvettetonybone Engine 17 04-13-2013 08:31 PM
the history of chevy v8's savman1 Hotrodders' Lounge 43 03-02-2012 06:57 PM
Pinging on 03 Chevy 5.3 Engine in Suburban bry21317 Engine 42 10-02-2011 07:35 PM
Valve Lash adjustment hiball Engine 36 05-11-2009 10:12 AM
engine swap question earthworm Engine 17 12-08-2003 01:53 PM


All times are GMT -6. The time now is 09:34 PM.


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.