390 flywheel on a 360?
 

Hello all!
This is my first attempt at the world of mixing and matching Fords.
I have a 360 that came with an automatic, and I need to put it in a '78 one ton with a 4 speed.
Will a flywheel form a 390 work on my 360?
I saw some posts that were both pro and con.
Little help please, before I get it all together.
Thanks,
Mike

390 flywheel on a 360?
 

They're the same, go for it.

Barry

390 flywheel on a 360?
 

Thanks Barry. Good to know these things before I drive it off a cliff in frustration ! ! ! :D
How about the pilot bushing, a common part?

390 flywheel on a 360?
 

Like the man said, their the same. :-X06

390 flywheel on a 360?
 

There's no reason to believe me, but I'm going to say it again. I took a 360 out of my '74 F250 that my brother rebuilt himself. It was over 150K miles and getting old. I decided to build a 390 and got another block, crank, rods, etc. The 360 that was in the truck was (I believe) a '68 that had been rebuilt.

When I was done putting the 390 together, I used the harmonic balancer and flywheel from the 360. It VIBRATED LIKE HECK!

I went out and talked to an FE guru here on the Island who built 100's of them and he said "No way you can use that 360 flywheel on a 390". He sold me a flywheel and I got another balancer from a junkyard. Ford parts department also said they were different part #'s for the balancer, but not sure why.

Anyway, I put the flywheel and balancer on it and it ran great! I did try just the balancer before taking out the 435NP, and it still vibrated, so it had to be the flywheel.

WARNING - I know all the FE gurus here will say I'm nuts. But please, before you put the engine all together and install it, make sure the flywheel doesn't have any weights cast or welded to it. Also, check the balancer and make sure it's appropriate for the crankshaft you are using. Just to double check.

NOTE: This was from a normal-snout 360, it was not some kind of FT 361. The flywheel DID have cast-in weight and the two balancers were VERY different.

GURUS: If you want to argue with me, take it to email. I don't mean to fill up the forum with flames.
:D

art k.

390 flywheel on a 360?
 

Krewat, no flames intended, but just who is this long island 'guru' ? I think he either doesn't know what he is talking about, or he is blowing smoke up your backside. Anyone who has built 'hundreds' of FEs will know that the 390 and the 360 have interchangeable balancers and flywheels. Maybe your brother used some nonstandard parts when he rebuilt the 360 ? Maybe he thought he had a 360 and was mistaken? something ain't right here......DF

390 flywheel on a 360?
 

I had a 360 in my 75 f100 and put a 390 in and used all the parts off of the 360 and it all worked fine.

390 flywheel on a 360?
 

My brother used an un-rebuilt '68 360 ... I checked the crank code, and it was a standard 360...

I may have shown that guy the flywheel I used and it had a cast-in weight on it. His words were "can't use that"... but, I'm pretty sure on the phone he was of the opinion that I couldn't interchange them.

I don't recall his name, but he built plenty of 428CJ for Mustangs and other 60's/early 70's Ford's. I spoke to a lot of machinists and they all knew him by name, and said if anyone knew, it was him.

Funny thing is I asked Ford parts dept, machinists, everyone I could find. More than 2 people said that they WERE different. I don't know why... I have to look through all my stuff in storage and see if I can find that balancer and flywheel.

Again, just check it before you ASSUME. All I'm saying is I've been bitten by the "sure they interchange" statement. Always a GOOD idea to look before installation.

One thing, the flywheel from that 360 had a coarse-tooth ring gear. The passenger car 390 had a fine-tooth ring gear.

art k.

390 flywheel on a 360?
 

Hey Guys,
I just did this with advise from the Forum. My 360 with a 4 speed took a dump. And I bought a complete 390 with an automatic. Had the same questions. I took my Flywheel, Clutch assembly and Bell Housing from the 360 and put them on the 390. No problems at all. I would go for it.
:cool:

390 flywheel on a 360?
 

Krewat, you're not totally nuts. I don't think. I've read the same thing myself, on a different form (fordfe.com), with the same (andr warmer) discussion around it. Most everybody agreed that the FT engines were externally balanced, while most of the FEs were internally balanced, so that the flywheels from 360s and 390s would interchange just fine. This sounds completely reasonable. Still, there were a few people that insisted that you could not interchange these two flywheels. I see no reason why you can't swap flywheels between these motors.

I was getting a horrible vibration from my 360 flywheel (on a 360) above about 1300 RPM once, but I took it to a machine shop that balanced it by drilling out metal, and that fixed the vibration wonderfully. It was difficult finding a shop that was able to balance flywheels, but it didn't cost much at all (around $50), and my comfort and the longevity of the engine internals were certainly worth the effort. Even though my engine crapped out shortly after that...

390 flywheel on a 360?
 

If you go to autozone and order a flexplate for a 390 you will get part number FRA-212. If you get one for a 360 you will get part number FRA-212. The flywheels and flexplates are the same. There's no maybe about it. Each and every 360/390 made was balanced internally. The flywheels must maintain a zero balance. Each and every 361/391 was balanced externally. There are no exceptions. I'm sorry this is just fact. Somebody made a mistake in engine identification somewheres along the line when the flywheels were swapped or the other engine was previously rebuilt and got a funky balance job.

390 flywheel on a 360?
 

I had a 360, verified by the crankshaft BY ME, with a counter-weighted flywheel. I do not know why, but it is the TRUTH. My brother rebuilt a stock '68 360. And didn't get it balanced and it didn't vibrate horrendously.

Amazing how some people read books, work on motors, and never understand that somewhere in the statistical universe there is actually something that doesn't conform to the "facts" as they know them.

Cut it out - it was a 360 - verified by crankshaft code. It had a counter-weighted flywheel. I used it on a 390 which vibrated badly when first started. Changed the flywheel to one without the weight, and it worked fine.

All I'm saying is MAKE SURE before you install the motor. It's a simple thing to check.

This is how flame-wars start. Some guru has all the answers and probably does. Then he comes up against something that goes against the "facts" and keeps stating his position. Enough.

I got bitten by the "sure they interchange". period. Believe it or not. Either way, err on the side of caution.

art k.

390 flywheel on a 360?
 

Art, you are wise to suggest a good look at parts before bolting them on, most of these engines are 35+ years old, and who knows WHAT may have been done to them before you got ahold of it. As a perfect example, your 360 had the wrong flywheel on it......DF

390 flywheel on a 360?
 

Yeah, good point. I never meant to say it wasn't the wrong flywheel :)

art k.

390 flywheel on a 360?
 

Great thread guys, and thanks for all the input.
Okay, did the F150s come with 361s, or just the "big" trucks?
My engine came from an F150.
I will check to see if the flywheel has any weights on it.
The HB is the unit that came on the engine.
Love this site, thanks.
Mike