Technical 9" Long Style Pressure Plate Bolt Pattern

Hi Guys,
I'm having my flathead flywheel drilled for a 9" long style pressure plate, but my machinist is telling me I can save a bunch of money if I can get him the actual bolt pattern for the pressure plate.
I know this has been discussed to death but I've never seen the pattern anywhere.

I've searched high and low and the best I can come up with is that the bolt pairs are 2.830" apart on center.
Anybody know the pattern or where I can find it?
Thanks,
Phil

 

Probably a good idea to purchase the pressure plate you intend to use, don't you think?

 

Search on the Fordbarn. There have been several posts, some with dimensions but i think there was a really good one on how it was layed out. Try to get a rebuilt plate...there have been issues with new ones. You might be able to guess where new ones come from nowadays...
Even the pattern is a bit dodgy on those, stamping uneven or warped or something.

 

Yeah, I don't intend to extrapolate the pattern from the stamped steel cover... I'd expect that to be pretty variable. Even one of my original ones.
I have a place that's going to rebuild one of mine with slightly stiffer springs.

I searched fordbarn but didn't come up with anything. I'll dig deeper though. Thanks!

 

I haven't found the good one yet...the following are some that contain bits of advice that might be useful.
The classic lightened flywheel assuming pre-8BA motor, is the rimmed type used about 1935-1941. These are already drilled for 9 and just shaving off the big rim that surrounds the clutch gets rid of a lot of weight.


http://fordbarn.com/forum/showthread.php?t=37253&highlight=drilling+flywheel
http://www.fordbarn.com/forum/showthread.php?t=137303&highlight=pressure+plate&showall=1

 

Yep, I saw those two. Not sure about indexing off the old holes. That would seem to take a lot for granted. I bet 9 times out of 10 it works fine, but I promise I'd be the 10th.

I hear you about the 59a flywheel... I wish I had that problem.

Thanks again Bruce!

 

Ron's trick of making a centering piece and drilling though a 9" wheel is pretty interesting.

 

Assuming that a 1972 nine inch long style clutch is the same dimensions.. 5.125 radius....32° between holes, 3 places..0°/32°--120°/152°--240°/272°..

 

That certainly seems like the best combination of DIY and accuracy.

If I can find one, I might try it.

 

Slight wrinkle, someone offered me a 9.5" flywheel for the taking... So I just want to verify before I turn him down...
It's my understanding that the 9.5 Long pressure plate wont work with an early toploader... And also, that even if you could get it to work, the 9.5 is close in weight to the 10 and much heavier than the 9, so the benefit would be minimal.
Are these assumptions correct?

 

I think so. I do know of someone who had a 9.5 rebuilt with early arms, but I don't see much benefit to using one.