[67Fastback35]

Does anyone know if I can use the same flywheel on a 289 for a 351W? Is the bolt pattern on the crankshaft the same for these two motors?

[curtisboyte]

I would like to know also.

[rj8806]

Originally Posted by 67Fastback35

Does anyone know if I can use the same flywheel on a 289 for a 351W? Is the bolt pattern on the crankshaft the same for these two motors?

As long as they are both from the same era, i.e...both from the '60' - '70's where they were all 28oz counter balance weighted flywheels. The bolt patterns are the same from this era. I believe this changed in '79 when the fox body platform came out and they started calling the 302 a 5.0. The 5.0 went to a 50oz counter balance. They are not interchangeable.





Richard
Tech Support
Tremec TKO, T45 & T56 Transmission Systems

[The Greek]

All 289s and 351s are counterbalanced at 28 ounces and the flywheels are interchangeable as long as their diameter is the same. If the diameter is different you will have starter placement problems.

The 5.0 HO engines have a different balance factor of 50 oz. and their flywheels will bolt up to the 28 oz. engines, but the engine will develop a destructive vibration. This balance factor started with the 1982 and later 5.0 HO only. The same holds true for the harmonic balancers.

[sparx]

I have this question also. I had a 289 with c4 in my car, now I am building on a later 302 block that has roller cam provisions.

I was told the harmonic balancer has to be changed from 28 ounce to 50.

What about the flywheel? Does it need to be a 50 ounce? I believe the one I removed from the 289 is 23 oz.

And is there any difference between auto and standard trans regarding the required flywheel? I see many 50 ounce flywheels for clutch provision on Ebay but none for auto.

sparx

[66 restomod]

You must match the flywheel to the harmonic balancer of your engine or will vibrate itself to death in short order.
rj8806 is correct with his information.
I changed out my flywheel on the 289 when I did the T5 conversion to the 5.0 version so I could run a 10.5 inch clutch. The flywheel was a Zoom Flywheel and it was for a 289, 302 or 351 and came with bolt on weights for making it a 28 or 50 oz imbalance. I used the 28 oz weight on the 289.

To answer the original question: Yes the 289 with a 28 oz will fit a 351 and work. All 351 engines had a 28 oz imbalance

Good Luck and Be Safe
Ron
Christophers 66 Mustang Restoration and Modification

[sparx]

thanks!
How does the flywheel index? The harmonic balancer has a keyway to index, none on flywheel?
sparx

[66 restomod]

Originally Posted by sparx

thanks!
How does the flywheel index? The harmonic balancer has a keyway to index, none on flywheel?
sparx

The holes on the flywheel look like they are the same distance but they are not. It will bolt up only 1 way.

Good Luck and Be Safe
Ron
Christophers 66 Mustang Restoration and Modification

[sparx]

Originally Posted by 66 restomod

The holes on the flywheel look like they are the same distance but they are not. It will bolt up only 1 way.

Good Luck and Be Safe
Ron
Christophers 66 Mustang Restoration and Modification

Ok you are speaking of the spacing then...
jim