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Flexplate/ Starter;

392 Views 16 Replies 5 Participants Last post by  crjackson
Hi, there's a 141 tooth flexplate on my 302 windsor. I have difficulty finding a 9 tooth pinion starter. [If this is the correct starter.]
I note 157 and 164 tooth flexplates are most common.
Any issues if I change my flexplate to a 157 or 164 tooth? Is this what's normally on a mustang 302 5L. engine?
My engine is an 'F' code... so guessing its around the mid 1970's era.
Also, is it a 28 or 50 balance weight that's needed on the flexplate?
A 3/8 or 3/4 offset? Is this the height of the ring gear or something to do with the starter?
Many thanks in advance for any info on this!
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You should be able to get the proper starter and flexplate by going to an auto parts store and telling them what year engine and car it came from.
Hi, I'm in Ireland and these parts aren't readily available over here. Also I've no idea how old the engine is... as it's not the original in my 1974 machine 11.
There are engine casting numbers that you can look up that can give you this info. Rockauto.com is a good source for parts or a way to obtain part numbers.
A Guide To Ford V8 Engine Block Casting Numbers, 1952-1996 (enginelabs.com)
Hi, I'm in Ireland and these parts aren't readily available over here. Also I've no idea how old the engine is... as it's not the original in my 1974 machine 11.
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I'm confused here. Your avatar shows a 1968 Mustang in it but you say that you have a 1974 Mustang...
Where are you getting the F code from exactly? I assume it's the VIN so if you have the VIN that the engine came out of then post it here.
What's a "machine 11"?
If this is a 1974 Mustang then you're going to have to make modifications to get the drivetrain to fit in the car. Ford had to redesign most of the front of the Mustang II in 1975 to shoehorn a 302 in the car.
The bellhousing and flywheel always have to match each other since if they don't then your starter won't be in the right location. The 141 tooth flexplate was used on the 1975-78 Mustang II and also the 1979 Mustang. Being just 12" it had a smaller diameter than most because of the tiny bellhousing that was necessary in the Mustang II. It has a 28 oz weight. Part # D5ZZ6375A
This is the modern replacement for it: More Information for ATP Z251 (rockauto.com)
You can't install any other automatic bellhousing and flexplate in a Mustang II without cutting apart and welding the car so forget that idea. You simply need a Mustang II starter for the applicable C4 auto trans. I assume that you're using the C4 that was originally installed in the Mustang II?
If you're using a 1975-79 302 and trans from a Mustang and it's going into a Mustang II then just buy the matching Mustang II starter. It's an incredibly tight fit btw. It's a unique starter to fit that bellhousing and it has 9 teeth. I believe that the industry part # is 3124. Those starters are cheap here in the USA.
1975 FORD MUSTANG II 5.0L 302cid V8 Starter Motor | RockAuto
His avatar looks to be a 67, no side marker lights.
That's great info, thanks. Rockauto give extra detail... like number of teeth on pinion etc.
I'm confused here. Your avatar shows a 1968 Mustang in it but you say that you have a 1974 Mustang...
Where are you getting the F code from exactly? I assume it's the VIN so if you have the VIN that the engine came out of then post it here.
What's a "machine 11"?
If this is a 1974 Mustang then you're going to have to make modifications to get the drivetrain to fit in the car. Ford had to redesign most of the front of the Mustang II in 1975 to shoehorn a 302 in the car.
The bellhousing and flywheel always have to match each other since if they don't then your starter won't be in the right location. The 141 tooth flexplate was used on the 1975-78 Mustang II and also the 1979 Mustang. Being just 12" it had a smaller diameter than most because of the tiny bellhousing that was necessary in the Mustang II. It has a 28 oz weight. Part # D5ZZ6375A
This is the modern replacement for it: More Information for ATP Z251 (rockauto.com)
You can't install any other automatic bellhousing and flexplate in a Mustang II without cutting apart and welding the car so forget that idea. You simply need a Mustang II starter for the applicable C4 auto trans. I assume that you're using the C4 that was originally installed in the Mustang II?
If you're using a 1975-79 302 and trans from a Mustang and it's going into a Mustang II then just buy the matching Mustang II starter. It's an incredibly tight fit btw. It's a unique starter to fit that bellhousing and it has 9 teeth. I believe that the industry part # is 3124. Those starters are cheap here in the USA.
1975 FORD MUSTANG II 5.0L 302cid V8 Starter Motor | RockAuto
Thanks guys. Just to clarify...
Car in avatar in not mine.
Typo... predictable text... not "machine 11" but mach II.
I sorted the 3/4" offset, so I'll buy same to suit.
"F" with a few numbers is stamped on the engine block... so it's not the mustangs Vin number.
The car was restored and modified... which is probably why the 302 windsor and trans fits in it.
I would put your car in the avatar instead of one that you don't own.
With that flywheel you know that the car came out of a 1975-79 Mustang but what trans do you have in the car?
I assume that it's the C4?
What are the numbers on the bellhousing and trans? The trans will usually have a tag on the side as long as it was never removed.
Thanks guys. Just to clarify...
Car in avatar in not mine.
Typo... predictable text... not "machine 11" but mach II.
I sorted the 3/4" offset, so I'll buy same to suit.
"F" with a few numbers is stamped on the engine block... so it's not the mustangs Vin number.
The car was restored and modified... which is probably why the 302 windsor and trans fits in it.
No tag on trans, but it looks like a C4.
I will just replace 141 tooth flexplate and 9 tooth starter for new.
Just one more issue...:unsure: I've no idea what the black arrow-shaped switch is for? It can turn 90 degrees but can't pull it out.
I would put your car in the avatar instead of one that you don't own.
With that flywheel you know that the car came out of a 1975-79 Mustang but what trans do you have in the car?
I assume that it's the C4?
What are the numbers on the bellhousing and trans? The trans will usually have a tag on the side as long as it was never removed.

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That is a ball valve, follow the tubing and you will see what it's for.
Is there something wrong with your original flexplate?
It's clearly something that a previous owner put in there since that along with the green indicator light and button are where the vent is supposed to be.
The brand name is the clue. They apparently make compact high pressure ball valves as mentioned.
Parts of flexplate is ground away
.. worse than in other places.
Seller said original engine was a 2.8L. but he didn't convert it over.
Steering on opposite side to cars in the US.
What could a ball valve be used for and would it be of concern since I may have changed its original position?
Is there something wrong with your original flexplate?
It's clearly something that a previous owner put in there since that along with the green indicator light and button are where the vent is supposed to be.
The brand name is the clue. They apparently make compact high pressure ball valves as mentioned.
The original 2.8 flexplate wouldn't bolt up to the 302 since it would have a smaller bolt pattern. It also would have had 138 teeth and had 11 5/8" diameter. If the flywheel that's on it now has 141 teeth then that's the correct 302 flexplate.
As 07redstang said you have to look and trace the tubing to wherever it goes. Pull out the instrument cluster to see or look up underneath the dash if you can.
That is a quarter turn ball valve on your dash. It is a good valve. WHY it is there is a mystery to me.

1/4 turn ball valves are used for ON-OFF applications for all different kinds of fluids to allow and/or block flow (e.g., instrument air in a factory to an air tool, chemical injection into a piping quill, etc...)
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I'm not sure why there is a VACUUM gauge right below that valve, but it could have been plumbed into the vacuum gauge. That being said, I'm not sure why you would need to isolate (open, allow / block, close off) vacuum from a dash gauge.

I'm guessing there is another gauge or two perhaps not shown in your pic. Is there a fuel pressure gauge? An oil pressure gauge we cant see? Vintage era engines would have these tubed into the dash gauges that had an actual spring gauge.

But then people started figuring out electrical sensors are WAY safer. Not everyone wants 65 psi of HOT OIL pressure staring them in the face directly on the dash.

+1 --> you are going to have to look at the back side of that valve to see what is plumbed (tubed) into. Trace it out and you will find your answer.
Copper tubes comes in and out of that valve. See top right hand corner. They seem to go through the firewall.

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As mentioned earlier just trace the tubes to where they go and it'll reveal what it was for. Perhaps it was a haphazardly installed nitrous valve.
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That’s what I was thinking too…
Perhaps it was a haphazardly installed nitrous valve.
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