360/401 differences

[jarcher401]

Replaced the 360 in my J10 with a 401 and ran into a snag installing the alternator. Seems the threaded hole in the 401 heads for the pivot shaft for the alternator is 7/16-14 thread as compared to 3/8-16 for the 360 heads. The alternator will not slide on a 7/16 dia. shaft. I ended up threading both ends on a 7/16 shaft and drilling out the brackets and alternator housing to be able to slide onto the new shaft. What gives? Why the difference. I checked a couple parts stores and they both take the same alternator.

[ironman_gq]

I think they use the same heads too. The difference depends on which end of the head you are looking at and maybe the year they were built. I think the older alternators used larger hardware than the GM style ones

[msalaba]

It's the year. I don't know the break but I ran into the same problem. Had a '73 304 and then got a '78 360. I put the assessories fro the 304 on the 360 and had to drill out the alt sleeve. Been working flawless for 5 years.

The 360 didn't come w/ assessories so I don't know if it was a braket re-design or not.

[ironman_gq]

I think the break came along with the GM style alternators around 78. Had the same problem with my CJ had a swapped in 304 with the Ford style alternator and I put a GM type in and had to drill out the sleeve on the alternator and the spacer to make it work.

[jarcher401]

Interesting, I know over the years Jeep did alot of sourcing of the charging system along with other items. Just seems odd, I know the 401 was from a 78 Chief and my 360 was a 79. Oh well we jumped that hurdle, thanks a bunch. Can't wait to get this thing fired up.

[jarcher401]

Well the 401 is finally in. I have the J10 in my basement garage where there is no driveway per say just yard, and wouldn't you know I now have about 27 inches of snow and my plow is in my other garage. I still had to break in the cam, so I borrowed a length of exhaust hose and ran it out the side door. Everything went well, no leaks or anything. got 60 lbs of oil pressure cold and 23 at idle hot. H P Engines out of Mifflintown, Pa. did the rebuild and so far everything is top notch. They are very knowledgeable with AMC engines. Went the whole Edelbrock Perfomer route along with the shorty headers.
(Two notes of interest here is they found that the front oil passage was not drilled on the Edelbrock cam and cast flashing in the upper timing gear oil passage, both of which they took care of. Something to watch for with Edelbrock.) Charged the AC while I was at it too. The engine wiring harness and pre bent stainless brake lines came from Z&M Jeeps and can't say enough about them. Brake lines fit perfectly and the only modifications that I had to make to the wiring harness was to tie in a feed for the anti diesel switch for the carb, which I'm assuming didn't come on the later FSJ's which I fed off the automatic choke and eliminate the wire going to the oil pressure switch since I am now running a mechanical gauge and go to a newer transistor ignition box off a Grand Waggie to utilize the newer weatherpac connectors and put weatherpac connectors on the wiper moter which Z&M supplied. Now all I gotta do is put the hood back on and wait for some of the snow to melt before I bust out of the garage.
http://i103.photobucket.com/albums/m157/lasteagle/j10401engine001.jpg
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[retrorod]

Looks good I bet you cant wait to drive it! I know that I wish my 401 was done and in my jeep. :lo1l: :razz:

[jarcher401]

Finally got out of the garage and have been putting on the miles. Had a starting problem after hot which drove me nuts for awhile but turned out to be a faulty stud connection on the starter side of the starter solenoid. Installed a new one along with some #2 ga. cables and all is fine. Even with the 3:07 gears this thing is quick off the line, can't say what top end is but my kid said he hit 100 mph pulling a slight grade on the interstate and it still had more. Got more guts than I do but then it ain't his truck either. Having a blast at the stop lights though. Shocked alot of unsuspecting youngans in their euros. Whose going to give a clapped out plow truck a second look? Oil pressure still good at 60 cold 23 at idle hot and around 50 cruising. Running the Brad Penn partial synthetic 10w30 racing oil which has the higher zinc to keep the cam happy. Gas mileage of course is in the single digits but creeping up to 10 but don't expect much better, especially if the kid drives it.

[sprink669]

sounds like fun! I worked in Mifflintown PA. wow what a small town. I worked at the courthouse remodel. I have a 401 in the garage that I want to rebuild some day. :lo1l:

[jarcher401]

do it. cost the same as any other amc engine but loads more fun.