401 Flexplate Revisited

[OBX_Commando]

I'm running a '75 mildly built 401 with my stock 1973 Commando Turbo400 transmission with the two piece case and crank spacer. Which flexplate works?? [img]/ubbthreads/images/graemlins/wall.gif[/img]

Last summer when I did the installation I lined up 3 different 401 and 360 flexplates with my old 304. None seemed to work and I so went with a rebalanced stock 304 flexplate. The 304 flexplate worked fine until I broke it a couple of weeks ago gettin' down hard on the 401. [img]/ubbthreads/images/graemlins/burnout.gif[/img]

Now my search has started all over again. I have reread the old threads that I can find on the subject and it seems that several of you have gone with the rebalanced 304 plate and have been happy or maybe a 360 plate of some early year.

Is a rebalanced 304 plate the way to go or is there some other mystery flexplate that works also?? and is there a source for that plate?

I know we've been over this before, but for those of us in the cheap seats can I get some help once again.

Thanks [img]/ubbthreads/images/graemlins/cool.gif[/img]

[dfjeepster]

Unfortunately there is no factory jeep aplication that had a 401 with a TH400 in 72/73 using the crank spacer/offset flexplate setup that the Commandos and early Wags had. You can still get 304 and 360 flexplates for this setup that have the proper balancing and offset, I posted a name of a company awhile back where I got my 360 unit from pretty cheap but I've lost it from my favorites so you may have to search for it. Or you can try finding one at your local auto parts place by application for a 72 Wag with a 360. Anyways as you said your choices are to use a rebalanced 304 or 360 plate. I'm not sure if the 360 one is any beefier but if you have to get a new one anyway it can't hurt to go with a 360 one and then get it rebalanced to the 401.

[72morph]

I moved the weight from a 401 plate to a 401 offset plate.Seems ok.I got a plate for the 74 wagoneer 360 from a place I found on the search.Not too expensive.Autozone can get plates about $55 if memory is right.I had a good 401 plate for an AMC bolt pattern and bolted every thing and then found out starter nose was dragging on gear and way out of location.401 came around when amc bolt pattern was being used with no adapter. Bop trans,spacer and adapter won't work with any plate that is specific for the 401.
As a side note a plate is also made to fit the 727 trans and 401.This is something I used in my 88 waggy.I think the place in Florida AMC Performance? is where I got that one.
In further ramblings,the th400 plates suck as they break at the thin sections and warp and hit the starter gear on torque up making a rather scary noise.We found that out by power jacking waggy with the brakes on and watching sparks fly off the starter.
Remember 304,360,and 401 are all externally balanced different.Harmonic balancers are also all different.Probably way to much info,good luck.

[RRich]

Not sure if they can help - but they are specialists in flywheels etc. They even can build you what you want. A phone call is cheap.

Clutch Masters in Colton Ca.

[OBX_Commando]

Thanks for everybodys help. I think I'll find a couple of '72/'73 360 and 304 flexplates and sit them side by side and see if the offsets are the same and if one is more beefy then the other. While I'm doing that I may also talk to a couple of transmission places and see if there is anyone around that builds custom plates, maybe I can have one built thats tough and suits my application.

I'm sure this will all help the next guy doing a 401 conversion also.

Thanks
-Ron [img]/ubbthreads/images/graemlins/beach.gif[/img]

[72morph]

I want to correct my post.I moved the weight from a 401 AMC bolt pattern fly wheel for the th-400 to an off set one for the 72 waggy 360.Sorry for the cornfusing post.Let us know how it runs when you get it finished.I don't have doors or seat belts on mine and the hole shots will really pucker you up.Needs an e-locker on rear,tires are expensive.

[OBX_Commando]

I had my local parts house order me in flexplates for both a '73 Commando auto w/304 and a '72 Wagoneer auto w/360. Since they had different part numbers and the price was a little different, I wanted to compare them before I made a selection. It turns out that they are identical. They have the same look, feel, shape, cutouts, offset and they weigh the same. There is no difference between the two that I could see. Of course the dude behind the counter could not tell me why they are priced different, he is just a clerk and has no idea Jeep made a Commando.

So I ended up with a 304 flexplate for about 45 bucks. I moved the weight over from an old 401 plate put it all back together and at least that little problem is solved. A new transmission problem has now shown up but I guess I'll start a new thread for that.

The 401 is runnin' great. Thanks for everyone's help.
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