73 j4000 Nailhead 400 to amc 400?

[ridenrace6]

when i bought this truck about 3 year ago the previous owner had removed trans because the bellhousing was cracked really bad. my trans builder couldnt find a nailhead case but did find a amc case.
i have removed the belhousing adapter, flexplate and associated spacer, also i have gotten a new pioneer flexplate along with new arp flexplate and converter bolts, also got a new crown trans mount. i also purchased a new trans to tcase adapter and d20 twin stick kit from bjs.
i just now am getting around to try and get this thing back on the road and have run into a little hickup, the dust cover and thin plate behind the flexplate, ( i dont know the proper name for it ), doesnt seem to work with the newer trans, also i got a newer 360 that had a 727 trans with the truck but no dust cover, does anybody know if the thin plate from it will work?
if not could somebody direct me to a source for the parts i need and the proper name, and maybe a pic of the correct parts?
engine in the truck is the original 73 amc 360.

[ridenrace6]

it’s been a week and no info, am i the only one who has done this?

[wiley-moeracing]

Your trying to hook up an amc trans to a bop motor, will not work, you need an amc motor to hook up to an amc trans or a bop trans to a bop motor.

[ridenrace6]

Originally Posted by wiley-moeracing

Your trying to hook up an amc trans to a bop motor, will not work, you need an amc motor to hook up to an amc trans or a bop trans to a bop motor.

negative, since when did buick make a 360?
73’s had amc engines

[fulsizjeep]

I didn't realize the plate on the back of the motor was different for AMC V8 to BOP T400. I have one from a 76 AMC V8 to AMC bell T400 if that is what you need.

[ridenrace6]

Originally Posted by fulsizjeep

I didn't realize the plate on the back of the motor was different for AMC V8 to BOP T400. I have one from a 76 AMC V8 to AMC bell T400 if that is what you need.

thats what i’ve been trying to figure out, nobody has given me a definite yes or no on whether they are the same, i only know that the dust cover i have from the bop trans doesn’t seem to work with the amc trans.
can you post a pic of the 76 plate you have?
or if your willing to ship i’ll buy it, i can at least get trans in that way, i will however still need a dust cover.

[wiley-moeracing]

It says nailhead 400 to amc 400? Did not say anything about a 360? Now I am confused

[ridenrace6]

Originally Posted by wiley-moeracing

It says nailhead 400 to amc 400? Did not say anything about a 360? Now I am confused

im sorry if i didnt put in enough info, i'll add it to the original post.
i did say 73 j4000 tho and its my understanding everything after 70 had amc engines, and 73 was last year for bop trans, 74-79 were amc engines and amc trans.

[wiley-moeracing]

Yes correct but at some point someone may have replaced with a different motor and driveline, happens all the time.

[tgreese]

Jeep never offered the BOP TH400 transmission. They either adapted the nailhead transmission to their engines with a ring adapter, or they used a TH400 with a direct-to-AMC-engines case. Nailhead is not BOP. Starting in 1980, they switched to the A727 transmission, a Chrysler 727 with a case matching the AMC engines.

The part between the flexplate and the block is called a spacer by Jeep. All three of the above applications use different parts here. A '73 should have a nailhead transmission, and its spacer is a 3184901. Around '74, Jeep switched to the AMC-case TH400, which uses a 5357217. Not surprising, the A727 spacer is different, PN 3213743.

IIRC Ristow has covered the nailhead-to-AMC TH400 conversion, and said it works without any changes. Certainly you can get parts for the AMC case (convertor, flex plate) easier than for the oddball nailhead implementation.

Post in the WTB forum here and at fsjnetwork.com. There are Wagoneer-only wrecking yards; Montana Overland, Jakes, likely others that are Jeep-only. See if you can locate a Wagoneer locally by checking enigines or transmissions on car-part.com It's not a part that wears out; you just need to find one.

[fulsizjeep]

Here ya go. There are two plates hanging on the nail. This plate also fits the 727 configuration (80-91).

[ridenrace6]

i tried to post pics of what i have but it says they are too big, anyway i have a plate for the 727 trans and its the same as the one posted above but when i put it on trans dowel holes to see how it fits its lopsided so bad i dont see a way of ever getting a dust cover to fit
also the nail head and 727 plates are same thickness

[tgreese]

This antiquated site will not host your pictures unless they are too small to matter. Host your picture on another site and post a link to it. Make sure the site allows public viewing, and that you set the permissions for public viewing.

[ridenrace6]

a little update

thanks to jeep recyclers i now have the spacer plate and matching dust cover and inspection plate for the 74-79 turbo 400.

i ordered few other things along the way, all of which ive already received.

new pioneer flexplate from oreilleys for the 74-79, pilot bushing from novak, new rubber trans mount, new dana 20 twin stick kit, and a new trans to t-case gasket from bj's, new arp flexplate and converter bolts from summit, and i went to the local tractor supply for grade 8 bellhousing bolts.

i have a couple of questions tho, both relating to engine balance.

1. will the factory harmonic balancer work with the 74-79 flywheel or do i need a 74-70 balancer?

2. the small ring that goes on the flexplate where it bolts to crank is slightly differrent between the 73 down that came off the jeep and the spare 80 up engine i have in shop, so the question is wif one of these will work, which one, or do i need to get one specifically for 74-79?

[Rod2]

Wheeeee! You automatic guys are a blast. My T-18 and I just don't get it.

[ridenrace6]

Originally Posted by Rod2

Wheeeee! You automatic guys are a blast. My T-18 and I just don't get it.

thanks, that helped a lot....

[tgreese]

Originally Posted by ridenrace6

a little update

thanks to jeep recyclers i now have the spacer plate and matching dust cover and inspection plate for the 74-79 turbo 400.

i ordered few other things along the way, all of which ive already received.

new pioneer flexplate from oreilleys for the 74-79, pilot bushing from novak, new rubber trans mount, new dana 20 twin stick kit, and a new trans to t-case gasket from bj's, new arp flexplate and converter bolts from summit, and i went to the local tractor supply for grade 8 bellhousing bolts.

i have a couple of questions tho, both relating to engine balance.

1. will the factory harmonic balancer work with the 74-79 flywheel or do i need a 74-70 balancer?

Do you mean flywheel or flexplate? The terms are not interchangeable. The 360 flywheel is different for 1971, and for 72/73. There is no change in the 360 flywheel '74-80. No info whether this reflects a change in balance due to the change in HB; probably. '71 is different because the crank flange is different, I presume.

2. the small ring that goes on the flexplate where it bolts to crank is slightly differrent between the 73 down that came off the jeep and the spare 80 up engine i have in shop, so the question is wif one of these will work, which one, or do i need to get one specifically for 74-79?

Jeep calls that a "Spacer, ring gear flex plate to crankshaft." That too changes between '73 and '74 and is unchanged through '79 (the last of the TH400). '80 up is for the TorqueFlite transmission (A727) and undoubtedly different.

[ridenrace6]

Originally Posted by tgreese

Do you mean flywheel or flexplate? The terms are not interchangeable. The 360 flywheel is different for 1971, and for 72/73. There is no change in the 360 flywheel '74-80. No info whether this reflects a change in balance due to the change in HB; probably. '71 is different because the crank flange is different, I presume.
Jeep calls that a "Spacer, ring gear flex plate to crankshaft." That too changes between '73 and '74 and is unchanged through '79 (the last of the TH400). '80 up is for the TorqueFlite transmission (A727) and undoubtedly different.

yes flexplate, its a auto trans, flywheel would be for a manual trans.

so your saying i need the spacer ring for a 74-79?

will i also need a harmonic balancer or are they the same thru the years?

[tgreese]

Change in part number only tells me that the part changed, not how it changed. In the day, Jeep would have considered two different part numbers to be incompatible, unless the parts book specifically says to substitute one number for another. Sorry, I don't have anything better for you.

This topic has been covered before. I recall there was a change from the 3-bolt to 4-bolt HB, but I don't know more than that. You could search and read old posts - that's what I'd have to do to help you further. You realize that the forum is archived specifically to help you with this kind of research? You're the one with incentive to pursue this question.

Example https://www.bing.com/search?q=site%3...+3-bolt+4-bolt Works with Google and other search engines too.

[ridenrace6]

another update, ive got the trans and t-case bolted to the engine but have run into another roadblock.
while trying to get the crossmember in i cant seem to get the mount on the t-case to line up with any of the holes in the crossmember, does anybody know if the cross member changed from 73 to 74 up?
also as all the driveline except the engine was already out of the truck when i got it, i cant seem to locate the8 bolts that mount the crossmember to the frame, does anybody know the thread size and pitch and how long they need to be?