6.9l vs 7.3l idi flywheel balance question and bellhousing question

[Jjona5]

Can I use a 6.9l flywheel on a 7.3l engine? I just stumbled into a sweet 7.3l engine when I was looking for some parts for my 95 powerstroke. I have a 78 ford with a 4 speed manual transmission(400m big block bellhousing). I have been getting conflicting internet information on two issues:

First Issue:
I found a bell housing, flywheel, clutch, and pressure plate for a 6.9l from an awesome guy on here. Some posts on here say the 6.9l flywheel will be fine on the engine but some information on fordtrucks.com says otherwise

(from the other site)Flywheel -
IMPORTANT. DO NOT USE 6.9 flywheel or vibration damper on 7.3 or vice versa. If components are intermixed, engine vibration and premature component wear may be encountered. For identification, compare these part numbers.
Vibration damper 6.9 1805414C1
Vibration damper 7.3 1809117C1
Flywheel Auto 6.9 1803219C1
Flywheel Auto 7.3 1809212C1
Flywheel manual 6.9 E7TA-6477-AB
Flywheel manual 7.3 E8TA-6477-AA

Now if that really is the case, how could I use my 4 speed on a 7.3l? I don't want to have to make up all new drive shafts if I swap over a 7.3l transmission and transfer case. Plus my 4 speed is pretty awesome. At 70mph with my big tires and gearing the truck only turns over 1400 rpms. Also would that mean if I use the 6.9l flywheel I should put a 6.9l damper on there?


The second question.
I have read that the 460/351m/400m bell housing will work on the 7.3l is that the case?\


I appreciate any assistance.

 

[Knuckledragger]

It is OK to use 6.9 balance parts on a 7.3.

Some of the differences shown as part numbers reflect that the 7.3 was paired to the E4OD transmission, while the 6.9 was with the C6. They used different flexplates. Other reasons could stem from the slightly heavier rotating mass of the 7.3, since it is basically a 6.9 with .110 larger diameter pistons. Later 7.3 (1993-94) had larger wrist pins and heavier rods for factory turbo applications.

Ideally, you would want to balance all of the rotating parts together for smooth operation. If you just want to get it on the road, use whatever you have and be on your way.

I have read that the big block (460) bell housing is the same as the IH diesels. That would make sense, as Ford really didn't want to cast special housings for the diesel tramsmissions, so required IH to make the bolt pattern the same as the big engines. Don't know about the 351.

 

[fordf350man]

the gas bellhousing is different, the 460 bellhousing will not bolt up to the 7.3, i am not sure if the 351m and 400m will bolt to the 460 i think they will but dont take my word on that, however the 460 can be re drilled to bolt onto the 7.3 diesel, there is a thread on here somewhere that has a picture and shows what holes need to be made in order for it to fit, personally i would get the transmission for the diesel but that's just me but it has been done

 

[Jjona5]

So I should probably get a vibration damper for the 6.9 then eventually. On the note of the bell housing. I have 400m which is kind of the ******* child of the Cleveland, Windsor, and big block family. It has Cleveland heads, Windsor style oiling system, and a big block style bell housing.

I appreciate the help.

 

[FarmerFrank]

Yes 351m and 400m = big block bell. Same as 429/460. 289,302 and 351W = small block bell. 352, 360, 390 , 428 = FE bell housing.

Isn't ford great at that?? You can make the BBF bell housing work on a diesel and as for balancers I'd try to get one from the same engine as the flywheel if your worried too much but they are both the same

 

[Double-S-Diesel]

ive used a 6.9 flywheel on a 7.3 a few times

 

[hce]

Mounted on a crankshaft balancer, the 7.3 and 6.9 do read a significant difference of imbalance.

 

[73IDI]

I use a 78 4 speed and a 6.9 flywheel and bellhousing on my 7.3 with no issues other than its low geared and I made my own clutch fork and the geometry must be off causr the pedal is stiff but it all works fine

P.s. mine was a 351m and I used that clutch and pressure plate

sent from my phone so my spelling and grammer most likely suffer more than usual

 

[Jjona5]

Hmm. I actually have a brand new clutch and pressure plate in the truck(300 miles prob) burned a valve by doing something stupid right after a rebuild and fell into this engine. How did you do the engine mounts? Did you just cut the old ones off the donor truck?

 

[73IDI]

Well everyone seems to do it differently but I unbolted the part that the mounts go through if you look on the cross member you should see how they unbolt and cut that up and fabbed my own mounts but ive heard 460 mounts that fit your 78 or 79 will work but idk.....the advantage to making your own I think is you can position the motor where you like it my set up allowed for a turbo without the need for a body lift like some guys have asked me about

sent from my phone so my spelling and grammer most likely suffer more than usual