400 or 455 swap into '66 Lemans - Pontiac GTO Forum
User Tag List

 
LinkBack Thread Tools Display Modes
post #1 of 5 (permalink) Old 07-14-2009, 08:14 PM Thread Starter
 
Join Date: Jul 2009
Location: SF Bay Area
Posts: 23
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
400 or 455 swap into '66 Lemans

From what I understand, all Pontiac V8's from the 326 to the 455 have the same outer dimensions, but would I have to change anything if I swapped a 400 or 455 into a '66 326 car? Motor mounts, etc? I'd rather have a 389 or 400 but I'm leaning toward a 455 since they're bigger AND cheaper.

The trans is a 2spd, probably an ST300 but could be a Powerglide. I know they worked okay behind a 389, but it's the original trans with 180,000 miles on it and I'd much rather have a 200r4 or TH350.

And finally the rear end is most likely a pegleg, and I want posi. Would a later (68-72) rear end work?
JB_Finesse is offline  
Sponsored Links
Advertisement
 
post #2 of 5 (permalink) Old 07-14-2009, 08:46 PM
 
Join Date: Oct 2007
Location: Long Island NY
Posts: 4,702
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Garage
The 455 will go right in. You should use a TH400 trans. The 68 rear is 1 inch wider than the 66, but will fit. You MAY need diffrent coils for the rear swap. Eric



Eric Animal is offline  
post #3 of 5 (permalink) Old 07-14-2009, 09:09 PM Thread Starter
 
Join Date: Jul 2009
Location: SF Bay Area
Posts: 23
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks Eric. What would I have to do for the TH400 though, use a '67 GTO console and shifter?
JB_Finesse is offline  
 
post #4 of 5 (permalink) Old 07-15-2009, 08:39 AM
 
xcmac26's Avatar
 
Join Date: Nov 2008
Posts: 489
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
TH400 bolts right up to the 400 engine, it's what's in my car. Nothing fancy about it.
xcmac26 is offline  
post #5 of 5 (permalink) Old 07-15-2009, 08:41 AM
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)
Straight bolt in stuff. You're 2 speed would even work....it's stronger than a TH350 or a 700R4......
geeteeohguy is online now  
Sponsored Links
Advertisement
 
Reply

  Pontiac GTO Forum > The 1964-1974 Pontiac Tempest, Lemans & GTO > 1964-1974 Tempest, Lemans & GTO General Discussion

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 GTO 455 engine swap pbkgto 1964-1974 Tempest, Lemans & GTO Complete Engine Compartment Discussion 8 04-16-2009 08:34 PM
Valve Cover Opinions Please Koppster 1964-1974 Tempest, Lemans & GTO General Discussion 42 02-19-2009 09:13 PM
71' Lemans motor swap Lemansdude 1964-1974 Tempest, Lemans & GTO Complete Engine Compartment Discussion 11 01-20-2009 12:26 PM
400 or 455? rod collins 1964-1974 Tempest, Lemans & GTO General Discussion 9 01-28-2008 04:38 AM

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