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Replacing AMC 304 with AMC 360 in 78 Pacer |
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mantonas
AMC Apprentice Joined: Mar/21/2015 Location: Knoxville, TN Status: Offline Points: 196 |
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Posted: Feb/10/2018 at 6:14pm |
As the subject says, I have a 78 Pacer with a factory 304 V8 engine. The original engine was already blown when I bought it. I know that I'm going to have to transfer some Pacer-specific stuff from the old engine onto the replacement, and I think I have a handle on that stuff. But today as I was thinking about the project, I started wondering whether I was going to have any balancing issues with the torque converter and flywheel. I bought a 360 to install on craigslist and it has a flywheel on it. I haven't checked the number of teeth to make sure it matches the one in the Pacer; assuming it does, will I have any balancing compatibility issues if I stick the 360 with its flywheel into the Pacer using the Pacer's torque converter? FYI, according to the guy who sold me the 360 engine, it came out of an 80s Grand Wagoneer.
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1972 AMC Javelin SST
1973 AMC Ambassador 401 1975 AMC Pacer D/L 1976 AMC Pacer X 1976 AMC Matador sedan 1978 AMC Pacer V8 coupe 1987 Jeep Grand Wagoneer |
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wantajav
AMC Addicted Joined: Sep/04/2009 Location: PA Status: Offline Points: 1150 |
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What plate is on the 360 now?..... "Flywheel"....
If it is thick/heavy steel donut that is a manual transmission pressure plate. The flex plate for an automatic is thin, looks like Its $28 bucks - you need a 360 one. I think you need to remove a pilot bushing from the crankshaft if it was a manual transmission on the Jeep. Reuse your 304 exhaust manifolds on the 360. Edited by wantajav - Feb/10/2018 at 7:00pm |
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one bad rambler
AMC Addicted Joined: Jan/09/2008 Location: On The Island Status: Offline Points: 2007 |
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The word Flywheel has been mis taught forever ..just like a sway bar ...it`s a stabilizer bar....Confirm that your torque convertor fits in your crank and all 4 bolts line up with the holes in the flex plate
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68 AMX 390 4 Speed,68 American,64 American 2 Door Wagon Altered Wheelbase,78 Concord Build 360,727,8.8
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mantonas
AMC Apprentice Joined: Mar/21/2015 Location: Knoxville, TN Status: Offline Points: 196 |
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I can't go look at the engine right now because it's in a storage unit, but I'm pretty sure what it has on it is like what's in the link you sent. Most of my V8 engine experience is with mopars, and they have a flexplate bolted to the crankshaft that bolts directly to the torque converter. If the engine was externally balanced, then you had to use the right harmonic balancer on the front of the engine, and if I'm not mistaken the torque converter also had to be one that was for an externally balanced engine. The round plate on the back of the AMC engine that we're talking about, which I always thought was called a flywheel, is integral with the torque converter on mopars. That's why I'm asking this question, to find out if AMCs had this balance issue and if so what to do about it.
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1972 AMC Javelin SST
1973 AMC Ambassador 401 1975 AMC Pacer D/L 1976 AMC Pacer X 1976 AMC Matador sedan 1978 AMC Pacer V8 coupe 1987 Jeep Grand Wagoneer |
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mantonas
AMC Apprentice Joined: Mar/21/2015 Location: Knoxville, TN Status: Offline Points: 196 |
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I think the exhaust manifolds on the 360 will work, because if I am not mistaken they are the same for Pacers and Grand Wagoneers. I might have to swap the oil pan. I know for sure that I am going to have to swap the timing cover, because it is Pacer-specific. That actually concerns me a lot, and I was going to start a separate post about it, because the timing cover contains the oil pump, and if the 304 engine is blown, it might have been due to low oil pressure, which means I should rebuild the pump, which I think involves machining the inside of the timing cover and shimming the moving parts of the pump.
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1972 AMC Javelin SST
1973 AMC Ambassador 401 1975 AMC Pacer D/L 1976 AMC Pacer X 1976 AMC Matador sedan 1978 AMC Pacer V8 coupe 1987 Jeep Grand Wagoneer |
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401jim
Supporter of TheAMCForum Joined: Jan/07/2012 Location: Brunswick,Ohio Status: Offline Points: 793 |
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304 and 360 front covers are the same and you will not have to exchange them. The flywheel that came with the 360 will have to be used along with the harmonic balancer from the 360. both engines have specific external weights and can not be used on a different cubic inch engines. hope this helps you.....Jim
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401MATCOUPE
AMC Addicted Joined: May/20/2010 Location: Salisbury, MD Status: Offline Points: 5368 |
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I have done this swap before, 304 to 401, since the 304 uses a 998 trans and 401 normally use the 727....you would need to shorten the driveshaft, but he 998 will certainly bolt right up to the 360. In mid/late 80 Wagoneers (GW) went to a different flex plate.....personally if you have it apart put a new one in.
Pacer exhaust manifolds are unique and the GW one will not fit, just reuse the ones you have. Pacer V-8 timing cover is not different BUT the oil filter adapter and gasket are completely different, ao you need the special gasket and adapter need to be swapped.....the GW oil filter adapter will drive the filter right into the rack and pinion steering gear. Use all the Pacer accessories and bracket up front and you should have no other issues that I remember.
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Ross K. Peterson
68X,GoPac,343,AT,52A(1stCar) 68X,GoPac,390,4sp,52A 69X,GoPac,390,4sp,64A 70X,GoPac,390,4sp,87A,8 70X,GoPac,390,4sp,BBO,8 70 Jav SST,390,AT,BSO 74MatX,401,AT,Prototype 74MatX,401,AT |
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mantonas
AMC Apprentice Joined: Mar/21/2015 Location: Knoxville, TN Status: Offline Points: 196 |
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That's good news about the timing cover, I just need to swap the oil filter adapter. Now I guess I just need to worry about whether the torque converter and flex plate will match (i.e., fit together and bolt up).
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1972 AMC Javelin SST
1973 AMC Ambassador 401 1975 AMC Pacer D/L 1976 AMC Pacer X 1976 AMC Matador sedan 1978 AMC Pacer V8 coupe 1987 Jeep Grand Wagoneer |
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harry401
AMC Apprentice Joined: Feb/03/2018 Location: FL Status: Offline Points: 33 |
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The 304 likely has a lockup converter and trans I have a 998 bolted to a 360 no lock up. If your 998 trans is marginal I would get it rebuilt before throwing a 360 in front of it
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401MATCOUPE
AMC Addicted Joined: May/20/2010 Location: Salisbury, MD Status: Offline Points: 5368 |
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If you are going to use your original trans, then the torque converter is not and issue to bolt up to the 360 Flax Plate.....harry401 is giving good advise on the trans condition, if it is questional then rebuild it before you put is back in the upper trans bolts are difficult to get to......when I swapped the 401 in the car I did , I put engine and trans in as one piece from top, saved a lots of grief.
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Ross K. Peterson
68X,GoPac,343,AT,52A(1stCar) 68X,GoPac,390,4sp,52A 69X,GoPac,390,4sp,64A 70X,GoPac,390,4sp,87A,8 70X,GoPac,390,4sp,BBO,8 70 Jav SST,390,AT,BSO 74MatX,401,AT,Prototype 74MatX,401,AT |
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