304 vs 360 flex plate - JeepForum.com
 
LinkBack Thread Tools
post #1 of 8 Old 06-30-2017, 08:04 PM Thread Starter
chris989604
Registered User
1980 CJ7 
 
Join Date: Sep 2013
Location: las vegas
Posts: 392
304 vs 360 flex plate

Hello,

I was getting ready to drop in the new 360 build and realized my machine shop used the 360 (3 convertor bolts) when balancing the assembly.

The flexplate for the 304 that i removed Has 4 convertor bolts. It was bolted to a 904. The 360 was out of a wagoneer, maybe a 400t or 727.

Anyway, I always thought the 304/360 had the same external weight and were interchangeable. My machine shop is not so sure. They can not look at it until Wednesday and i was hoping to drop it in this weekend.


Any knowledge will help

chris989604 is offline  
Sponsored Links
Advertisement
 
post #2 of 8 Old 07-01-2017, 05:24 AM
Matt1981CJ7
Web Wheeler
 
Matt1981CJ7's Avatar
1981 CJ7 
 
Join Date: May 2011
Location: Elbert
Posts: 18,770
I know the flywheels are balanced differently for the 304 and 360, so I assume the same applies to flex plates.

Matt


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Matt1981CJ7 is offline  
post #3 of 8 Old 07-01-2017, 04:14 PM Thread Starter
chris989604
Registered User
1980 CJ7 
 
Join Date: Sep 2013
Location: las vegas
Posts: 392
I used rock auto and looked up parts mid 70s. 304 and 360 use the same flex plate when mated to the same 904 transmission. if it is a 400t or 727 it called for a different part number.

that is not saying rock auto is correct, I have ordered enough parts that are not right.

I guess i will wait and have the machine shop check the balance. No since is ruining the build on the last day.

Thanks,
Chris
chris989604 is offline  
 
post #4 of 8 Old 08-20-2017, 07:32 AM Thread Starter
chris989604
Registered User
1980 CJ7 
 
Join Date: Sep 2013
Location: las vegas
Posts: 392
Quote:
Originally Posted by Matt1981CJ7 View Post
I know the flywheels are balanced differently for the 304 and 360, so I assume the same applies to flex plates.

Matt
Matt,
You are 100% correct.

The flex plates are also different. Anyone reading this, I would not ever order a replacement flywheel or flex plate without having a machine shop balance them to match the one you are replacing.

Mine took a substantial amount of added weight to bring the 904 plate to match the 360.

Hope it helps someone.
Chris
chris989604 is offline  
post #5 of 8 Old 08-20-2017, 10:46 AM
simpleones
Registered User
 
Join Date: Jul 2017
Posts: 2
Garage
727 has a much heavier flex plate. 400t very thin and flexible. Just an fyi
simpleones is offline  
post #6 of 8 Old 08-21-2017, 08:59 PM
CSP
Registered User
 
Join Date: Aug 2002
Location: Colorado
Posts: 16,116
727, 904 and 999 use the four bolt flexplate while T400 is the three bolt, and yes they are displacement specific regardless of what transmission is behind the engine.
CSP is offline  
post #7 of 8 Old 08-24-2017, 10:02 PM Thread Starter
chris989604
Registered User
1980 CJ7 
 
Join Date: Sep 2013
Location: las vegas
Posts: 392
Quote:
Originally Posted by CSP View Post
727, 904 and 999 use the four bolt flexplate while T400 is the three bolt, and yes they are displacement specific regardless of what transmission is behind the engine.
That's the thing, they are all different but if you go to order one, they are all listed under the same part number 304- 401 .
chris989604 is offline  
post #8 of 8 Old 08-25-2017, 12:02 PM
CSP
Registered User
 
Join Date: Aug 2002
Location: Colorado
Posts: 16,116
Yep, I'm aware of that. It doesn't change the fact that the engines all require their own specific flexplate. A machine shop can determine the balance of an existing flexplate and match a new one to it.
CSP is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com 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 e-mail address for yourself.



Email Address:
OR

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
Show Printable Version Show Printable Version
Email this Page Email this Page



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 Off
Pingbacks are On
Refbacks are On

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