Technical Who has a flathead Ford with an 11" clutch?

I do have a 9” flywheel. Let me pull it out tonight and send some pics of it.

 

Keep in mind, an 11" clutch can have the same clamping force at a lower spring pressure due to it's greater surface area. This can help your thrust bearings. I would investigate how what you have is sprung, before I wrote it off. I've had 11" Long clutches in my OT '72 Bronco that were from butter smooth (auto parts store replacement) to, "Now I know why my left knee needed fixin'. " (McLeod, like the max they had, I thought more was better. I get in that car now and can't believe I drove it). Same car, same leverage, different springs. Mike

 

PM sent!

 

For your consideration.
Here's some info from The late "Rumbleseat", aka Paul Garrigan.
He ran a 9" clutch with heavier pressure plate springs in his "48" convertible pulling a trailer without problems.

 

I have an 11" that I tried behind a hemi with Ford Toploader, the counterweights would hit the Ford bellhousing when engaging the T-O Bearing, I switched to a 10" and it clears.
One thing about the 11" is that it has 3 sets of 3 springs, you can remove 1 spring from each set for lighter pressure and you'll still have all that extra surface area of the 11", it'd be easy to calculate it all out to figure out which will give you greater pressure.

 

Run the 11 in clutch, in the 50's everybody changed to the 11 in "Truck Clutch". Forget science and embrace tradition, use your 11 in clutch.

 

Ran a super strong 296 flathead in my 37 woody, which I ran at the drags with a 9 inch clutch!!! Had 39 box and quickchange, always thought the clutch would soften the effect on the rest of the drive train. Ran mid 16's and very high 70's mph, always thought that was pretty good for such a heavy car.