Looking for Specific Info on 304 to 360 swap...

[jafo]

I found what I believe to be a decent 360. Problem is it is out of a jeep with an automatic trans. I understand that the flywheels will not enterchange between the 304 and 360 directly due to balancing issues. I also seen some Omix flywheels and the reviews were not good as some installed those flywheels unbalanced. That said, being the assemblies being externaly balanced, converting this engine over to a maunal trans isn't possible without a total rebuild so that the entire rotating assembly can be balanced. Is there info to the contrary? Is there a source of properly balanced flywheels out there for AMC engines?

 

[RiverandSand]

I found what I believe to be a decent 360. Problem is it is out of a jeep with an automatic trans. I understand that the flywheels will not enterchange between the 304 and 360 directly due to balancing issues. I also seen some Omix flywheels and the reviews were not good as some installed those flywheels unbalanced. That said, being the assemblies being externaly balanced, converting this engine over to a maunal trans isn't possible without a total rebuild so that the entire rotating assembly can be balanced. Is there info to the contrary? Is there a source of properly balanced flywheels out there for AMC engines?

I have seem them on Summit racing and Rockauto. If you get the proper flywheel you shouldn't really need to rebalance the entire rotating assembly. If the engine is in need of a rebuild then a balance would be a good choice along with all the other rebuilding processes.

 

[Lumpy Grits]

Stay away from Omix! It's China JUNK.
Does the 360 crankshaft have the counter bore for the clutch pilot bushing?
LG

 

[jafo]

Stay away from Omix! It's China JUNK.
Does the 360 crankshaft have the counter bore for the clutch pilot bushing?
LG

Good question. That I can't tell you. It's a three hour drive away. Just judging by the listing and pics. It's a '78 amc 360. I assume out of either a J10/20 or Wagoneer.

 

[jafo]

I have seem them on Summit racing and Rockauto. If you get the proper flywheel you shouldn't really need to rebalance the entire rotating assembly. If the engine is in need of a rebuild then a balance would be a good choice along with all the other rebuilding processes.

From what I read. AMC kept inner parts within a close weight tolerance allowing them to externally balance. Thing is, making sure the flywheel you're getting IS balanced. Hence the reviews claiming unbalanced flywheels. It's all for not if it doesn't have the counterbore for the pilot bushing like LG said.

Recaming my 304 with new timing set and a new intake is looking real appealing right about now. The rest of the engine is sound. Just looking for a little extra.

 

[RiverandSand]

I can understand your apprehension with 360, I would have someone snap a pix of the crank end. I can't imagine AMC using two different cranks one for an auto another for a manual. On some automatics the torque converter is centered in the recess of the crank (not sure about AMC). I checked Rockauto using a 78 J10 360, it shows a Pioneer flywheel, in the description says balanced and ready to install for 200 bucks.

 

[mtnwhlr]

I can understand your apprehension with 360, I would have someone snap a pix of the crank end. I can't imagine AMC using two different cranks one for an auto another for a manual. On some automatics the torque converter is centered in the recess of the crank (not sure about AMC). I checked Rockauto using a 78 J10 360, it shows a Pioneer flywheel, in the description says balanced and ready to install for 200 bucks.

 

[jafo]

I can understand your apprehension with 360, I would have someone snap a pix of the crank end. I can't imagine AMC using two different cranks one for an auto another for a manual. On some automatics the torque converter is centered in the recess of the crank (not sure about AMC). I checked Rockauto using a 78 J10 360, it shows a Pioneer flywheel, in the description says balanced and ready to install for 200 bucks.

I'll check that out. Thanks

 

[hagar]

The Jeep parts manual shows two different part numbers for the V8 crankshaft from 1976 on up: one for manual, one for auto.
Before that, I was thinking the autos just used the pilot spacer ring that went into the end of the crank for the snout of the torque converter to ride inside.

 

[hagar]

The Jeep parts manual shows two different part numbers for the V8 crankshaft from 1976 on up: one for manual, one for auto.
Before that, I was thinking the autos just used the pilot spacer ring that went into the end of the crank for the snout of the torque converter to ride inside.
The same cavity that the pilot bearing would press into.

 

[JR74CJ5]

Just did this...

Omix is junk.

I'm dissembling freshly built 360 to have it balanced this weekend... vibrates out of balance.

The general good plan is to have the flywheel and rotating assembly balanced.

Now, for you, if you were not going to re-build and just wanted to swap, and you're pretty confident the flexplate is the stock one, you can take any flywheel for the 360 (technically others too, but safe bet 360) even the Omix one and your flex plate for auto that's on it, to a machine shop and they can get close enough to the original you'd probably be fine on a budget swap. Nothing is better than a full balance though.

 

[jafo]

Ok. Puting together all the posts here and some I have read other places, it's making a little sense to me. Basically to use a 360 from a vehicle that came with an auto trans from the factory, it would need balanced because of the flexplate. Or is it came with a manual from the factory but was missing or needed replaced, then an aftermarket flywheel would probably work. So if I am to do this 360, with the current engine I am looking at, to be safe, have it balanced. Or find a 360 that came with a manul trans from the factory for a budget build.

I'll just keep looking around. Something will come up. Mean time, I'll probably just freshen the 304 up and go with that and maybe do a proper rebuild on a 360. I'll talk to my local machinist.

 

[JR74CJ5]

Basically to use a 360 from a vehicle that came with an auto trans from the factory, it would need balanced because of the flexplate. Or is it came with a manual from the factory but was missing or needed replaced, then an aftermarket flywheel would probably work. So if I am to do this 360, with the current engine I am looking at, to be safe, have it balanced. Or find a 360 that came with a manul trans from the factory for a budget build.

For my part - I was saying you can grab a aftermarket or stock flywheel for manual, and take it with the auto flexplate on the 360 currently both to a machine shop and have them match the weighting from the auto flexplate to the maunal flywheel.

But the last part of what you said is the safest. Have the rotating assembly balanced instead with a engine rebuild.

I'm currently back to bare block and have some decisions to make because I didn't do what I know I should have from the start...

Had this in:

Now it's fully dissasembled and machine shop told me a cylinder is toasted (was new) and he wants to re-check the block for possible cross bore vs correctly doing it from the last shop... I'm a bit salty...

 

[Project86]

Well how did all this turn out?

 

[JR74CJ5]

for my part - A lot of repaying money already spent with a new shop, but otherwise good. New pistons, etc.

Engine runs very strong now.

For OP - not sure! OP?