Pontiac - Street No question too basic here!

          
Reply
 
Thread Tools Display Modes
  #1  
Old 12-30-2024, 01:22 PM
John Milner's Avatar
John Milner John Milner is online now
Ultimate Warrior
 
Join Date: Nov 2004
Location: Oklahoma
Posts: 1,173
Default Th400 differences

I am needing to rebuild a th400 for a 1971 GTO project. I have a few cores to choose from but am not sure if one would have any advantages over the other. The car will be a street car with a mild 400.

The cores that I have narrowed down to are:

OG code from a 1970 442 Olds 455.

PX code from a 1976 Grand Prix 400.

PR code from a 1973 Grand Prix 455.

PR code from a 1976 Grand Prix 455.

Would either of these cores be better than the other?

Thanks

  #2  
Old 12-30-2024, 01:58 PM
PontiacHO PontiacHO is offline
Senior Chief
 
Join Date: Apr 2024
Location: Raleigh, NC
Posts: 467
Default

Found this thread:
https://forums.maxperformanceinc.com...d.php?t=415558

The Following User Says Thank You to PontiacHO For This Useful Post:
  #3  
Old 12-30-2024, 02:06 PM
PAUL K's Avatar
PAUL K PAUL K is offline
Ultimate Warrior
 
Join Date: Feb 2004
Location: Sugar Grove IL USA
Posts: 7,435
Default

The 70 should have the right drum to accept the good sprag .... I'd use that one.


That's a nice collection of cores you have

__________________
Go fast, see Elvis!
www.facebook.com/PaulKnippensMuscleMotors
The Following 2 Users Say Thank You to PAUL K For This Useful Post:
  #4  
Old 12-30-2024, 02:13 PM
'ol Pinion head 'ol Pinion head is offline
Ultimate Warrior
 
Join Date: Apr 2000
Location: INJUN Territory, Red State Merica!
Posts: 9,873
Default

Quote:
Originally Posted by PAUL K View Post
The 70 should have the right drum to accept the good sprag .... I'd use that one...
Exactly!

IF that 70 Olds shortail had been coded OW, then i wouldnt.
Would instead go through it & offer it up for sale to the discriminating '70 W30 restorer.

__________________
Buzzards gotta eat... same as worms.
The Following 3 Users Say Thank You to 'ol Pinion head For This Useful Post:
  #5  
Old 12-30-2024, 02:22 PM
Formulas's Avatar
Formulas Formulas is offline
Ultimate Warrior
 
Join Date: Dec 2004
Location: Wrecking Havoc In The Matrix
Posts: 3,333
Default

When i built my first TH400 i had 3 or so cores .. i had them all apart and cherry picked every component ... case, planetaries, drums and so on i looked at every wear point ... you would be surprised at whats worn in one trans is fine in another from lack of maintenance, overheating, and any other abuses

worked out great

__________________
........... The More You Follow The Herd The Less You Can Be In The Lead ..........
  #6  
Old 12-30-2024, 03:09 PM
JSchmitz's Avatar
JSchmitz JSchmitz is offline
Ultimate Warrior
 
Join Date: Jan 2000
Location: Union, MO
Posts: 2,364
Default

The case in my car is from an early 80's Cadillac IIRC. I was shaking my head when I looked it up years ago.

  #7  
Old 12-30-2024, 05:26 PM
John Milner's Avatar
John Milner John Milner is online now
Ultimate Warrior
 
Join Date: Nov 2004
Location: Oklahoma
Posts: 1,173
Default

Thanks for the replies. I will start with the OG transmission and hopefully it will rebuild nicely. Thanks for the input everyone.

The Following User Says Thank You to John Milner For This Useful Post:
  #8  
Old 12-30-2024, 07:45 PM
65 Lamnas's Avatar
65 Lamnas 65 Lamnas is offline
Senior Chief
 
Join Date: Mar 2023
Location: Pontiac, IL
Posts: 448
Default

Quote:
Originally Posted by PAUL K View Post
The 70 should have the right drum to accept the good sprag .... I'd use that one.


That's a nice collection of cores you have
The '70 will not only have the right drum to use the 34 element sprag, but it'll ALSO have the good center support that accepts the .040" spacer ring that protects the case.

The Following User Says Thank You to 65 Lamnas For This Useful Post:
  #9  
Old 12-30-2024, 08:07 PM
performerrpm's Avatar
performerrpm performerrpm is offline
Ultimate Warrior
 
Join Date: Jul 2007
Location: oklahoma
Posts: 2,407
Send a message via AIM to performerrpm
Default

dang ...guess i need to pull the 2 th400 cores out i got the other day an take a look for the date codes, where exactly are they.


maybe ill get lucky n have a good one.

was tgere anything special about the 74 trans 45t th400 cores?

  #10  
Old 12-31-2024, 01:41 AM
chuckies76ta's Avatar
chuckies76ta chuckies76ta is offline
Ultimate Warrior
 
Join Date: Jun 2004
Location: Alberta
Posts: 3,369
Default

As mentioned I think the Cadallic th400 core is the beefed up one. It's been couple years since I researched cores. I remember the cores that had the metal vent tube were better that the plastic ones. 34 element sprag. Direct drum out of the 4L80E transmission. You can also pickup a heavy duty snap ring for center support, and a case saver. Cheap insurance.

__________________
68 Firebird. IA2 block, 505 cu in, SD Performance E-head, Solid roller 3600 weight. Reid TH400 3:90 gear. 28" slick.
Best so far 9.95@135 mph. 1.39 60 ft.
76 Trans am, TKX .81 o/d, 3.73 Moser rearend,
468 with KRE D-ports, Doug headers, 3" Exhaust
950 Quickfuel.
  #11  
Old 12-31-2024, 09:44 AM
Half-Inch Stud's Avatar
Half-Inch Stud Half-Inch Stud is offline
Ultimate Warrior
 
Join Date: Jul 2000
Location: BlueBell, PA or AL U.S.A.
Posts: 18,889
Default

100% of the Olds internals are superior to any of the other posted cores.
Except the actual tail shaft for PMD will be best.

Pick the case you prefer for originality. I would use a Big Car case for the reinforcements.

The Following User Says Thank You to Half-Inch Stud For This Useful Post:
Reply


Posting Rules
You may not post new threads
You may not 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

Forum Jump


All times are GMT -4. The time now is 12:24 PM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017