28oz. or 50oz.?

[bdblevins]

I am putting a small bellhousing C4 in my 90GT. Before it had a large bellhousing pan-filled C4 with a 28oz. 164tooth flexplate. There was no vibration that I could tell. Now on the small bellhousing C4 that has to have a 157tooth flexplate do I use a 50oz. flexplate or a 28oz. flexplate? I really need your help I know a 90GT with a 5.0HO should be 50oz. but why did it run so smooth with a 164Tooth 28oz. on it ? Totally confised.
Thanks in advance,
Bobby

 

[giddyup306]

Use whatever your engine was balanced with. However, the flex plates might weigh different amounts and/or be balanced differently, and pose a problem.

 

[RatStang]

If you're running a stock rotating assembly, you should be running with a 50 oz. imbalance.

The tooth number in this particular case, doesn't really mean a whole lot. Larger diameter flexplate with have more teeth but the same tooth spacing. In other words: if it's larger and for the same motor, it'll have more teeth to accomodate the same space between teeth.

The imbalance should match that of your motor though.

As far as your not feeling vibration with your last setup... unless the weight is WAAAAAAY off (wobbling), then you may not feel the vibration unless the harmonic is really bad.

The recommended weight imbalance that you usually see for X bellhousing/transmission is about the application that, that particular tranny setup was originally meant for.

 

[bdblevins]

As far as I know it's ( except for a B cam) a stock 5.0. I am totally confused, this is only the second Ford I've ever owned. The first being a radically modified 2.3T Turbo Coupe. I haven't took the GT to the track or a dyno but from the seat of the pants feel it ran great. I just don't want to make a mistake and have to tear it apart again. Do you reckon it might be a 351? I read somewhere a 351 was 28oz. balanced?
I am totally confused, any help would be appreciated. A friend of mine that races a lot told me to put a chevy in it and not worry about the balance. But that's not a option. I love the sound of this Ford.
Any help is appreciated.
Thanks

 

[RatStang]

Well you're going to have to find out what motor you have in there. That's not something we're going to be able to help you out with.

 

[bdblevins]

Are there any numbers on a Ford Block to tell what it is and if so where?
Thanks
Maybe a 383 Chevy might not be such a bad idea!

 

[RatStang]

Look at the underside of the block near the starter then google that chit.


As for the 383... just sell the car and go get an S10.

 

[bdblevins]

I don't want a S10 even tghough I know some fast ones. I want the car I have or I would have bought a S10. I appreciate everyones help and I will get the numbers and find out what it is. I have been doing this for about 40 years but not with Henrys vehicles. Give me a little time I will learn. I never ran into an engine with so many damn different weight flexplates and filywheels. But it keeps you on your toes.
Thanks everyone

 

[bdblevins]

I wanna have a fast Mustang with a Ford engine. There are a lot of fast Mustangs here but nearly all have a Chevrolet engine. And that's what I want to beat. Ford!!!!

 

[gearheadboy]

I once had a friend put the 28oz flywheel (stick shift) on a 5.0 in a Mustang. YOU WILL KNOW if it is wrong. It vibrated like hell. Does it have the stock looking fuel injection? Does it have a factory hood? These MAY be tell tale signs as well.

 

[bdblevins]

Everythng looks stock, except for the lope of the B cam.
Bobby

 

[gearheadboy]

If its stock..I'd say you need a 50 oz small flex plate. I'd bet yours is actually a 50 oz.

 

[bdblevins]

I'm going to put a 50oz. on it and see what happens. That's what you run into when you buy someone elses car.
Thanks,
Bobby