1972 Pontiac Lemans 350 .. Building up - 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 10-13-2011, 08:26 PM
Pontiac Muscle Gearhead
 
Join Date: Oct 2011
Location: Illinois
Posts: 9
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
1972 Pontiac Lemans 350 .. Building up

hello again, i have the stock 72 lemans 350, 7H1 heads, but i already have an edelbrock intake manifold, 600 Holley 4 barrel carb, and headman headers, what else can i do to get more out of my 350? i am going to stick to Pontiac so preferrably whatever can be done to this engine, or if i should get a bigger pontiac engine (400 or 455). Also, i may purchase a 69 pontiac 350 and trans so any tips or advice?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 10-14-2011, 05:46 AM
BOBCRMAN@aol.com's Avatar
Member
 
Last photo:
Join Date: May 2002
Location: Holly, michigan
Posts: 8,119
Wiki Edits: 0

Thanks: 25
Thanked 266 Times in 249 Posts
You will find it is not cheap to build horsepower from a 350 Poncho. Most abandon this motor.

You need to build compression. Then build for mid range torque and horsepower. These aren't chevies.. The heads don't breathe and rpm is limited by the valve train.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 10-14-2011, 09:57 AM
quadrajunk a name earned
 
Last photo:
Join Date: Nov 2009
Location: Parts Unknown
Posts: 342
Wiki Edits: 0

Thanks: 3
Thanked 11 Times in 11 Posts
You can always go with a better cam. I haven't worked with a Pont 350 before as I have a 400
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 10-22-2011, 11:33 PM
Pontiac Muscle Gearhead
 
Join Date: Oct 2011
Location: Illinois
Posts: 9
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
yea i know many abandon it, it doesnt stand out at all from any other engines... and beertracker would you recommend me getting a 400 ? or should i just cam it?
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 10-23-2011, 11:09 AM
Thumpin455's Avatar
Ask me about Ethanol
 

Last journal entry: 65 GTO
Last photo:
Join Date: Aug 2009
Location: Michigan's U.P.
Posts: 155
Wiki Edits: 0

Thanks: 0
Thanked 4 Times in 4 Posts
The heads do breathe, but the ports utilize velocity instead of max airflow. The valvetrain isnt nearly as limiting as the stock cast rods and the high velocity ports. RPM isnt needed since the 350 share the same 3.75" stroke as the 400. The main difference, if not the only difference, between a 400 and 350 is the bore size, and the 350 cant be bored to a 400. Just not enough meat there. Everything on the 350 except the pistons and rings can be used in a 400 if the crank is rebalanced for the 400 pistons.

Since you have an intake, I will assume its a Performer, and headers, then all you really need is a cam and some valve springs. If your heads dont have the end bolt holes like Cobalt mentioned, then there are two ways around that. One is the brackets he mentioned, the other is a set of Ram Air manifolds for D ports. They run about $300 but will seal without the end holes, and not cost you lots of power like the log manifolds. http://www.ramairrestoration.com/cat...?cPath=31_2_21

Here are some inexpensive cams that work quite well. Despite what people say, Pontiac engines dont have to be super expensive to build, and often can be done cheaper than a power comparable chevy.

This cam would work well, have a nice idle, and make good power. http://www.summitracing.com/parts/SUM-K2801/

This one works good in 400s and 455s, and is a bit rowdy for a 350 but not terrible. http://www.summitracing.com/parts/SUM-K2802/

These two are ok in a 350, and shouldnt cause a loss of low rpm torque. With ported heads any of these cams would work even better.

http://www.summitracing.com/parts/CCA-CL51-232-3/
http://www.summitracing.com/parts/CCA-CL51-222-4/

The other thing you could do if you have an automatic is swapping in a mild stall. Any transmission shop will have what they call a Th400 high stall converter. Its a full size 13" converter with a stall speed between 1900 and 2200 depending on the engine and vehicle. Alternatively you could swap in an off the shelf 2200 or 2400 stall, they dont slip that much and will give you just a bit off the line without wasting lots of RPM. Those converters will fit either a Th350 or a Th400, so if you have one of those its an easy swap. Any gear it has now, as long as it isnt 2.41 or 2.56 will work, but there really isnt any need to go deeper than a 3.42/3.55, and that will mostly raise the highway cruise RPM. I like a 3.08 behind my Pontiacs, and also the 2.73 works well provided you dont cam the engine to have a hole at the bottom of the RPM range. You have more torque to start out than a chevy does, so you dont want to build it like a chevy, if you do it will be a slug.

If you find a 400 or 455 block later you can swap most of the stuff you have in your 350 to it. Those cams in a 455 would be a stump pulling highway cruiser that shreds tires for fun.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 10-23-2011, 02:27 PM
quadrajunk a name earned
 
Last photo:
Join Date: Nov 2009
Location: Parts Unknown
Posts: 342
Wiki Edits: 0

Thanks: 3
Thanked 11 Times in 11 Posts
Quote:
Originally Posted by Pont.72lemans
yea i know many abandon it, it doesnt stand out at all from any other engines... and beertracker would you recommend me getting a 400 ? or should i just cam it?
I have always been a fan of bigger engine equal more power potential depending on how much you want to spend. If the 350 meets your power and cost goals then it's the right platform.

I noticed you are from Illinois where at? I grew up south of Moline.

bt
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 10-23-2011, 08:48 PM
Pontiac Muscle Gearhead
 
Join Date: Oct 2011
Location: Illinois
Posts: 9
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
thanks thumper im checkin out those cams now, and beertracker im in joliet its a small world
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 10-23-2011, 10:03 PM
quadrajunk a name earned
 
Last photo:
Join Date: Nov 2009
Location: Parts Unknown
Posts: 342
Wiki Edits: 0

Thanks: 3
Thanked 11 Times in 11 Posts
Here is some more info on Pontiac cams.

http://psp.aquacomp.net/topic.asp?TOPIC_ID=4799 Stock cam for Pontiac 350 is 066.

http://www.dapa.org/building-a-stron...iac-camshafts/ Table in link comparing Pontiac cam duration.

The Pontiac 068 cam is almost identical to the Summit 2801 except the 2801 has a little more lift.

Changes to the valve train (high lift cam or milling head or head gasket compressed thickness) may require changing push rod length and changing from stock bottle neck rocker studs to ARP studs and poly locks. The ARP studs make the valve train adjustable. Once you get the cam, rocker arm, lifter and push rods installed run a mock up to determine if the push rods are correct length.

http://www.compcams.com/Pages/417/va...-geometry.aspx

The other thing you could do would be to install a ignition timing (weights) advance kit and re-curve the distributor.

I hope you end up with a strong running Pontiac!

bt

Last edited by beertracker; 10-23-2011 at 10:20 PM.
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
1972 Pontiac Lemans 7H1 Heads .. Exhaust Gaskets Pont.72lemans Engine 4 10-23-2011 12:43 PM
1972 Pontiac Lemans.. Looking for any and all parts!! Pont.72lemans Hotrodding Basics 1 10-14-2011 05:30 PM
Whats the gear ratio in a 1972 pontiac lemans lemans Transmission - Rearend 5 12-10-2010 07:24 PM
1972 Pontiac LeMans Brake Lights David Krogh Electrical 3 08-21-2006 02:26 AM
81 Pontiac Lemans R.E. jcarter Transmission - Rearend 1 10-30-2003 11:22 PM


All times are GMT -6. The time now is 02:23 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.