What are the standard issue brake drum size on the '65 Formula S?

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dibbons

dibbons

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My '65 Formula S has 10 inch brake drums, front and rear. But some previous owner swapped in a 489 case 8 3/4 read end sometime down the line. Did factory '65 Formula S vehicles have 10 inch drums all the way around? Thank you.
 

Yes, 10s all around. Finned or helmet may be variable, mine were helmets on the rear with a big brim extending over the backing plate
 
Yes, the drums seem to vary. Some have double "snow lips" which envelope the backing plate lip, and others seem to have just an inner lip, especially on replacements. My 1965 had a big spring on the circumference which people say is to dampen noise, but perhaps also increases heat dissipation. By the 1970's, I think most drums came finned. The photos in the FSM should be close to what was typical originally, though could have varied between MI and CA plants.
 
IMG_0457.JPG
So, these are 10" drums? Factory 273 4 bbl 65 Barracuda. Are the spindles the same for both small and large drums?
 
I re read my question....and I said it like Yoda, LOL. :realcrazy: I guess I wondered if they were 10's because someones fin comment gave me hope. I can use the spindles to do an aftermarket disc swap when the time comes. I have some 73 up disc spindles, but I'm afraid they will make the wheels stick out too far and the tires will rub.
 
They look like 9's to me as well. You need to pull one and measure to be sure. Hate to burst your bubble bur they may have different spindles too. I have seen different disc kits have different part numbers for 9 or 10" brakes.
 
9” and 10” use different spindles! I can pull you a set for 10” if you need them!
 
I appreciate it, but I'm good with what I have. If I convert them to disc, Scarebird makes conversion stuff for either one. I may hit you up for other stuff along the way though!
 
Clean up the drum and look, it should have numbers cast in it that say: "max dia 10.060" or max dia 9.060". Isn't that right?

drum.jpg
 
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