360 to 401: flexplate ?'s

[mark j]

I am at this very moment trying to do a 360 to 401 swap. I've read up on previous posts about retaining the 401 flexplate etc. I've run into a problem- the waggy I'm swapping the 401 into is a '72 and has the adaptor to mate the 360 to the T400. The flexplate for the 360 is convex side out so that the teeth are not too far away for the starter to engage. This puts the mounting points for the flexplate to torque converter further out to bridge the gap created by the adaptor. The flexplate for the 401 is exactly the opposite- it is concave side out so that the torque converter mounting points are recessed in the flexplate (Since there is no adaptor creating an additional two inches of space). If I flipped the 401 flexplate I may be able to make it work, however I won't have flush mounting surfaces between the torque converter and the flexplate. Looks like I'm up a creek without a paddle!!! Is it possible to have the 360 flexplate rebalanced to match the 401? They are otherwise identical, aside from the concave/convex thing, with the exception of the counterweights. Anyone out there with experience with this???? Thanks. I have pics on fullsizejeeps.com in the Technical folder- just have to figure out how to post them here :confused:

[mark j]

Hope this works: 360:
http://www.fullsizejeeps.com/jeeps/files/Technical/360FlexPlate.JPG
Here's the 401:
http://www.fullsizejeeps.com/jeeps/files/Technical/401FlexPlate.JPG

[Crazy_Jeepman]

Quick and easy thing that comes to mind is ditch that tranny and go with the AMC Cased TH400. I know you can have the flex plate balanced, however that sometimes is hard to have done.

[mark j]

I thought about the tranny swap- I'd have to change the output shaft as the donor jeep had the BW QTrac. My question is wether the tranny/engine combo would be shorter necessitating moving the transfer case??? The engine mounts were on the front two slots- I guess I could relocate the engine back an inch by using the back two slots. I was hoping to make this a one weekend deal but the Klank curse of the 360 to 401 swap has caught up to me too!!!

[Crazy_Jeepman]

I am reasonably sure the overall length will be the same or close to it. I had them side by side at one time to compare and they apeared to be the same, not exactly accurate I know, but you could measure that up pretty easy. More work I know, but at least you update the trans a bit and will not have to worry about future flex plate problems.

[ March 05, 2004, 11:41 PM: Message edited by: Crazy_Jeepman ]

[mark j]

The same including the adaptor on the earlier T400? Does it have a shorter bellhousing? I'm going to measure and see. This might not be too bad- my T400 is due for an overhaul. The donor T400 shifted beautifully- only problem is it leaks like nothing you have ever seen before!!! I'm hopeful it is a bad o-ring on the shift modulator and fortunately I have a new one! Thanks for the reply!!

[89grand]

Originally posted by Crazy_Jeepman:
I am reasonably sure the overall length will be the same or close to it. I had them side by side at one time to compare and they apeared to be the same, not exactly accurate I know, but you could measure that up pretty easy. More work I know, but at least you update the trans a bit and will not have to worry about future flex plate problems.I agree.

http://www.fullsizejeeps.com/jeeps/files/Misc-Pictures/forestservice.jpg

[Crazy_Jeepman]

Yes the AMC cased TH400 and the Nailhead Cased TH400 with the adaptor is what I compared the lengths to.

[mark j]

You just made me a lot happier with the situation I'm in! Looks like I get to learn how to change an output shaft tonight!

[Crazy_Jeepman]

Trans has to be completely taken apart, a rebuild kit and a how to video would be a good idea, GSMIKIE is selling the video. Good Luck with it.