What is my clutch size?

Pbum5

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Oct 27, 2004
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Minneapolis, MN
Have a 67 289 with a toploader 4-speed. Just wondering what size clutch I have. I think it’s a stock type and I am looking to upgrade when I do a 5 speed swap. I plan on keeping the original bellhousing and clutch setup. Just want to know if it’s a 10” or 10 1/2”. Do I have to stick with that size? Any recommendation on a clutch to use? I was thinking of a Hays setup. Got about 300 HP at the flywheel.
 
From my experience, you cant tell until you get it apart. My supposedly original 289/toploader combo turned out to require an 11"er once I tore into it. I had already bought (ebay) a stage 1 centerforce 10" which I now have shelved. I couldnt return it and couldnt bring myselft to putting on a smaller flywheel so I just got the 11" surfaced and picked up a CF dual friction. The dual friction is a really nice clutch without much pedal effort.

Sorry this want an exact answer, just reccomending that you take it apart first to verify. On a side note, if you happen to need a 10" centerforce, I've got one for cheap.

Trevor
 
If it's an original set up (stock flywheel) is will either be a 10.0" or 10.5" (11.0" will not fit) - sounds like you know this already. I believe only the Hypo's ran 10.5" in the stock form and all others the 10.0"...but who knows what happen to your setup in the past 40 years.

The good news is that you can run either a 10.0" or 10.5" setup on a stock flywheel (at least I did this with a Hays setup recently). Don't forget to get your flywheel surfaced.
 
One shop pulled my first clutch and said it was a 10.5 inch and they had to look around for one as they couldn't find one. Disclaimer: they were morons. For my second clutch change, I went to a local speed shop and they installed a CF II setup, 10.0 inch on the same flywheel that was resurfaced.
 
Lonn - if it turn out I need a 10” clutch I’ll PM for the CF kit.

Fastback – yeah no telling what’s under there after all this time.

I plan on swapping out the flywheel for a Steel one from Hays.

I guess that would also change the clutch size?

If it can accept different sizes is it better to go with a larger size clutch?
 
Most aftermarket flywheels are drilled to accept different clutch/pressure types and sizes (check w/ manufacture).

As for a bigger clutch, that depends on your motor and your expected drivability. Bigger stiffer clutches usually mean more leg power, but can be minimized by installing a hydraulic or cable clutch. Also the clutch material can be more "grabby" or cause "clutch chatter."
 
rpm has more to do with cast iron vs. steel. If it will see the high side of 5000 rpm very often, go with a steel flywheel. You don't want to learn the hard way when a cast iron flywheel explodes 4" away from your ankles.
 
fasttback said:
Most aftermarket flywheels are drilled to accept different clutch/pressure types and sizes (check w/ manufacture).

As for a bigger clutch, that depends on your motor and your expected drivability. Bigger stiffer clutches usually mean more leg power, but can be minimized by installing a hydraulic or cable clutch. Also the clutch material can be more "grabby" or cause "clutch chatter."
The Centerforce Dual Friction is the exception to that rule. Yea, it's more "grabby" at first, but after it breaks in, it behaves like any other stock clutch. But the pedal effort is less than a stocker, from day one. :nice: And it'll handle torque like no other stocker will. It's not the horse power the engine generates when it comes to clutch selection, it's the torque you want it to handle, especially when you bog the engine off the line or nail the pedal in too high a gear at too low a speed. THAT'S when the torque overcomes a stock clutch. I ran a stock type "heavy duty" 94-95 Stang clutch in my Ranger that didn't put out 300 hp, but even it over torqued that clutch with it's "high torque" F4TE roller cam.
 
Ok guys im bringing this one out from the dead. Heres a simple question..
I'll be running a late model roller 5.0 block (I think '87?) with a toploader that will fit it. (I've already verified that it will bolt up.) My question is this: Is the clutch needed for a '87 5.0 the same as the clutch for a 1965 289? Or are the clutch sizes different. Ill be running the flywheel that used to be on my 289. (157 tooth, 28 oz)
 
If I remeber correctly, the rotating assembly was balanced at 28 oz's to work with the rest of my old roatating assmebly. So assuming I go with my old 157 tooth 28oz flywheel, can i just go with an 87 clutchdisk/pressure plate set up?
 
What size clutch did the 289 flywheel have origially?
If the flywheel is not on the engine take it to the auto parts store and see if it matches. I have a 28oz and a 50oz flywheel from when I had a 5 speed and they would both use the same disc and plate. But I don't know about your 289 flywheel.
 
I would gladly do that if I wasnt at college and the car 200 miles away...:(
The flywheel is a 157 tooth, 28oz flywheel. Does anyone know what size clutch the original 289 used? I could probably have a friend go to my home and measure it for me. Would they simply measure accross the diamter of the disk to find the clutch size? Also, in terms of pressure plates..is there a difference between 289 and 302 pressure plates?
 
I dont know the exact year of the new block (DSS didnt realease that info to me.) But its a roller block, and if this is any help...I need the adaptor to be able to mount the z-bar set up onto the block. Gut feeling has me saying its around an 87.
 
BullittStangV8 said:
If I remeber correctly, the rotating assembly was balanced at 28 oz's to work with the rest of my old roatating assmebly. So assuming I go with my old 157 tooth 28oz flywheel, can i just go with an 87 clutchdisk/pressure plate set up?


You need to remember what it was..... otherwise Id like to hear your report when you bolt up a 28oz flywheel to a 50oz RA and rev er up :D
 
truuuuuust me...there is no way im turning over the motor untill I have all of the driveline components matched up properly. None of this would be an issue if the car wasnt a mix of components from different years. :notnice: The balancing of the motor is stamped on the snout of the crank, so mixing it up wont be an issue as soon as I can get someone to get over to check what it says..:mad: