401 into an '86 GW--what needs to be done?

[Paul]

Looks like I'm going to transplant a 401 from a '78 Wag into my '86 GW. My '86 has the TF 727. What needs to be done? I hear a different flex plate is needed--off what car and any suggestions as to where to get one? What about transmission kick-down linkages (has a Rochester Quadrajet)? Should I swap the Rochester and original AMC intake manifold for my Edelbrock/Carter set-up? Do A/C and power steering brackets bolt up the same as on my 360? Lots of questions, huh?
Thanks for your patience!

[Hump]

Good question Paul. I've not done it, so I can't answer, but I've also wondered about putting a 401 where a 360 used to reside.

Just moving it to the top to get noticed.

[Crazy_Jeepman]

A new flexplate for the 401 (Make sure it is one for a 401) and 727 Trans will be needed.
Your Edelbrock/Carter set-up should be fine but you will need a kit from edelbrock for the brackets that hold the linkages for the trany kickdown and throttle cable. The accessory bolt holes in the heads of your 78 401 will be a different size than those on the 86 360, so be sure to keep all the bolts for them. You will have to drill the mounting hole out on the 86 alternator so the long bolt will go through it and bolt into the head (78 bolt is bigger). Exaughst manifolds use two different size bolts on the 86 so beware of that. You will need to use the 86 exaughst mainifolds since the Y pipe is at a different configuration due to the drivers drop. (Needs to clear the front driveshaft) You will need to use the Ford style Starter not the Mitusbushi starter. I have been up for the last 20 hrs so I can't seem to recall if the Mitusbushi starter was used in 86 or not, either way it has to be the ford style that gets used, and yes I am aware I spelled Mitusbushi wrong. ;)

[oldyellowwagoneer]

I put a 401 in an '85 wagoneer,heres whats needed: 1) the proper flexplate.(I got mine from a place called MEFFORD AND SON in either tulare,ca or visalia,ca.don't know which for certain) 2)I put on a performer manifold and holly carb.I fixed the kickdown linkage by running a 2x1/4" bolt through the lower carb linkage hole pointing away from the carb,run a lockwasher and nut down to make it a solid stud,slip the linkage over the stud and installing a jamb nut on the outside.MAKE SURE YOU ADJUST IT PROPERLY!!!
3) you may have to space the throttle linkage back some to get full throttle,at least on a holley.run all the late model bolt ons keeping in mind that some holes on the cylinder heads may or may not need bigger bolts as crazy_jeepman said above.I dont know what the diff is with the starters but I dont see why you couldnt use the starter thats in there. good luck,DENNIS

[oldyellowwagoneer]

BTW, if you look around the hardware store there are threaded bushings out there that could be threaded into the cylinder head where the alt bolts to it,eliminating the need to bore out an alt that may be under warranty(that may void it). DENNIS

[andy d]

uhmm,this is hearsay, but havent i seen posts regarding early swaps onto 727 trans? iirc, you have to remove a pilot bearing from the early model engine to properly fit to the 727. if not removed, the pilot bearing breaks something in the 727

[gba-bob]

andy d is right. If your 401 was in front of an automatic it has a brass pilot bushing in the crankshaft that needs to be removed or the 727 torque converter will not fit. My transmission guy says the 727 flexplate from my 84 360 will work just fine behind the 401 so thats what I'm using. I've only started the engine in the driveway and there seems to be no excess vibration, it remains to seen if this is so on the street. (Fingers Crossed) So far the the 401 swap has been a pretty simple bolt up thanks to all the info I've gotten off this site.

[Paul]

Thanks for your help, everyone! By the way, to those who have done this swap: have you seen a noticeable increase in power over the 360?

[oldyellowwagoneer]

oops,forgot about that bushing.sorry :( my 401 came out of a standard truck.however you DO need to get the 401 balanced flexplate.that is a must.a friend of mine used the 360 flexplate and it started leaking oil at the seal and took out the main bearings.ask an automotive machine shop for proof. DENNIS

[gba-bob]

Oh man! I don't want to hear that. This means I have to rip everything apart again. Can I have the 360 flexplate balanced to a 401 like you can with a flywheel or should I have the 401 flexplate drilled to match the 727 torque converter? :confused:

[Bob Barry]

Just buy a proper flexplate for a 401 from a '73 Matador (or something) with the TF727 tranny. Yes, you'll have to pull something to access the flexplate, but you'd have to pull the motor in a couple weeks to change out the trashed bearings anyway, so it's just a matter of when you want to pull something.

BTW, the Mitsubishi starter was used starting in '88, and it required a flexplate with a different number of teeth. I prefer the Ford unit on my '78.

[andy d]

i too prefer the ford starter. its easy to replace and cheap to buy. ontoh, the mitsu is on its 2nd 360. :D paul is gonna have to go with a ford starter if he uses a matador flexplate

[Crazy_Jeepman]

I have seen a couple trashed 401's because a 360 flexplate bolts on so nicely. One thing to remember the type of vibration that the 360 flexplate on a 401 causes is rarely felt or noticed untill oil presure drops and the crank starts flopping around like a half dead fish, then its OOOOOOPPPPPS. Funny thing about the harmonics of the rotating assembly of an engine it MUST BE CORRECT. Speaking of harmonics, that is another round thing that can not be swapped from a 360 to a 401 or vice a versa. So moral of the story use the corect flywheels/flexplates/harmonic balancers on ALL ENGINES. Of course I am told rebuilding engines can be fun!!!! :D

[ December 06, 2001: Message edited by: Crazy_Jeepman ]

[gba-bob]

Thanks Guys, you saved me from myself again. Autozone has the flexplate for 47.95 (much easyer and cheaper then new bearings) At least I haven't put the front clip back on, so everything is still easy to get to. I can't wait to explane this to my wife when she sees the engine out of the jeep yet another time.

[dfitz]

Colorado FSJ web site tech section has an article of this subject, might be worth a look

Dennis

[RWC]

I JUST replaced the flexplate on my '85, and I was able to just slide the tranny back enough that I could get in there with a torque-wrench. Also, you should be able to find a flexplate for less than that. I picked up a new one for a 360 for $35 from 4-Wheel Drive Hardware.

RWC