Tried this post in the 385 forum with no luck..........

I have a 1978 460 (internally balanced) (1978 F250 2wd) and would like to put a flywheel from a 1984 460 (externally balanced) on the engine. This will work as long as I switch the harmonic balancer and spacer right?

 

i think so... but not 100%

 

NO! All externally balanced 385 series motors have the "hatchet" spacer between the front cover and damper. They also have a counterweight on the flexplate/flywheel. Internally balanced motors have a spacer behind the damper that has no "counterweight" on it along with a neutral balanced flywheel. Either way, there is no interchangeability between these engines in regards to flywheels and counterweights. The crankshafts are different. Internally balanced 460's have bigger counterweights that will not physically fit into externally balanced 460 blocks(casting D9 and later). Putting a neutral balance flywheel on an internally balanced 460 would be a very bad idea. It could be done, but you would have to remove the rotating assembly and have it internally balanced. This would require the addition of mallory(heavy) metal, which is very expensive. Either way, the answer to your question is no. Get a neutral balanced flywheel.

-Jared

 

Is there any benefit to externally balanced over internally?

 

Not really. Late model (D9) and later externally balanced 460's have cylinder bores that extend slightly farther into the crankcase than earlier internally balanced engines. This means that later blocks will allow greater piston stability in stroker applications. As far as stock stroke engine build ups are concerned, there is no real difference between the two. Some engine builders prefer the internal balance, while others prefer the longer more stable cylinder bores. Bottom line: all 385 series fords are awesome.

-Jared

 

Thanks guys! Trying to keep from buying the $600 flywheel kits from L & L for my engine swap. I have found several 83 and up flywheels at area junk yards, but won't do me much good with a 78 engine.

 

The cyl skirts are a little longer.The perfered motor for stroke build.

 

Do you have the dimensions of the flywheel? I have one I took off of my 460. I don't know what was behind my 460, I bought the engine alone. It's an internally balanced engine. I'm running an auto so I don't need it. If it's the same and you need it we can work something out.

 

As long as the engine it came off of is 78 or older (internally balanced) it should be good to go. I think the tooth count on the ring gear should be 184. Just let me know.

 

you can also have the later one zeroed at a machine shop have had several done for engine swaps I did with great results. all they do is drill the extra weight out and there ya go internally balanced flywheel. cost me less than a 100.00 to do it.

 

Thats what I hear. I see a few on ebay for around $100 + shipping. Either way it would be cheaper than L&L or Bronco Graveyard.

 

why don't you just use a 360/390 flywheel, clutch and preasure plate? i ran this set up on my 78 f-250 with a 460 for 8 years with no triuble at all. i do sugets running a named brand clutch as those cheap ones don't last.

 

I just found a couple 360 flywheels (car-part.com) and will consider this option as well. I read a couple of forums on this option as well. What pilot bearing did you use?