1966 Mustang 289 flywheel info needed

[Harleyfunds]

Hi, Need some info/help
Have a 1966 mustang coupe 4 speed top loader
I picked up a Rebuilt 289 that was in a 1968 mustang with an automatic trans.
It has a wide heavy damper wheel, so I want to match up the correct weight manual fly wheel and not have any vibration problems.
My old 289 has a smaller damper wheel, can I use my existing fly wheel or should I get one that is heavier to match the damper??
What kind of weight fly wheel am I looking for???
Thanks in advance for help and info.
...Harley

 

[Onetim]

You just need to make sure it's 28 ounce offset weighted, not 50 ounce. The wide damper with the internal offset weight is supposed to make up for the heaver rods and 3/8 inch bolts on a hypo engine that spins to a higher rpm, but it can be used either way. You may want to look under the oil pan to see what you have, also a great time to check bearing clearences, trust no one on a rebuilt engine.

 

[Harleyfunds]

Thanks for the reply,
How do I know what weight the damper is or the fly wheel??
Yep, Got the pan off,,, will be checking specs,,,

 

[Onetim]

The flywheel or flex plate should be marked for it's offset weighting, a balancing shop could test it for you or 1967 and older should be correct. I would have it tested if going used. With new you should be able to tell them what you need. Nothing to check on the damper, weighting wise, but check the condition of the rubber between in inner and outer band, and if the outer band has slipped or not, check that the timing marks are correct at TDC. There are a lot better dampers out there aftermarket, and you could get some cash the the old one, they can also be rebuilt.

 

[Harleyfunds]

many thanks,,,
when I pull the existing motor i'll check for its markings..
thanks again all the help ..

 

[GOvert]

Does the harmonic balancer have 3 bolt holes for the crank pulley or 4 ? 289s had 3 holes

 

[Harleyfunds]

It has 3 holes used to pull it,
and 9 other holes (not threaded) around the outside of the inner part before getting to the rubber, then the outside has 5 drilled balance holes ( not drilled all the way thru)

 

[Realmongo]

What is the casting number?