Flywheel and pressure plate question.

T

Torchie

Senior Member
I know that the 48 Ford flatheads used the the long style pressure plates. I believe that Trucks used an 11" while cars used a 10"
My question is this. Is the pressure plate bolt spacing different between a 10" clutch and PP and a 11" clutch and PP or the same? Is it the same flywheel and either set up will both fit or are the flywheels different.
Hope this makes sense and as always thanks for the help.
Torchie.
 
The bolt circle is larger (closer to the edge of the flywheel) on a flywheel drilled for an 11" clutch. The flywheel can be re-drilled for another clutch size at a machine shop.
 
If you want to use an 11" clutch on a '48 and earlier engine, you will also need the truck oil pan. The truck pan has a removable section under the flywheel to access the clutch. With a car oil pan, you will have to remove the oil pan to install/remove an 11" clutch and pressure plate.
Mark
 
But why would you want to use an 11 inch clutch/pressure plate unless you are planning on pulling tree stumps out of the ground?
 
JSeery said:
But why would you want to use an 11 inch clutch/pressure plate unless you are planning on pulling tree stumps out of the ground?
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Because that is what my truck had when it was built. Couldn't see finding another flywheel and pressure plate when all it needed was the clutch disc. It will probably out last me.
 
That is very true! Just a little more difficult to drive, but it is original. But, is Torchie talking about a truck (stump puller) or a car? :)
 
JSeery said:
That is very true! Just a little more difficult to drive, but it is original. But, is Torchie talking about a truck (stump puller) or a car? :)
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Well actualy I am talking about a early Ford trans to a Olds rocket engine combination. I know it's not Flathead(well parts of it are) but I am having clearance issues.
I see that there are two 11" Pressure plates offered for 48-64. 51-7563 and B8A-7563-B Anyone know what the differences are between the two? I know from some spec sheets that one has a bigger distance between the fingers than the other. Any thing else I should know?
Torchie
 
If you are interested in performance, the 11 inch would not be the best clutch/PP set up. If you are more interested in just getting it running it might be ok. I don't know the difference between the two you listed. 11 inch clutchs will have clearance issue in a lot of applications. Any reason you want to run it? A 10 inch or 9 inch would be a much better setup?
 
The only thing I can think of between the early 59A V8 and the late 8BA V8 11-inch clutches might be the size of the bolts that retain the cover. Both are Long types and both would be used on 1 3/8" 10-spline input shafts unless some of the later transmissions have a larger transmission input shaft. It might also be a difference in springs or spring pressures but I don't know for sure.
 
back in the 50's i had a 48 conv. with an Olds, i ran a 10" merc clutch and never had a problem, changed to a Caddy engine same clutch, much faster and no headaches, other than 2nd gear kept loosing teeth.
 
robert dick said:
back in the 50's i had a 48 conv. with an Olds, i ran a 10" merc clutch and never had a problem, changed to a Caddy engine same clutch, much faster and no headaches, other than 2nd gear kept loosing teeth.
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That Merc 10" clutch set up was common back then as well robert but you usually had to re drill the Olds flywheel for the 6 in a circle Merc bolt pattern.
The long style 3 sets of 2 bolt pattern on the Ford 11" truck PP is a direct bolt on to the Olds flywheel. As well as the Caddy flywheels of the same era.
My info indicates that the 51-7563 PP is the one that I need and that the one I have currently which has no markings on it at all may be the B8A-7563-B PP that has a larger distance between the fingers.
I was just surprised to see 2 different 11" PP that cover the same years. Maybe one was for light duty and the other for the bigger trucks???
All has yet to be revealed......
Torchie
Torchie
 
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