1970 Brake Rotors

[moonshine_mike]

Need some new front disc rotors for my 1970 cuda. Can't easily find 11.75" but see many 10.98". Does anyone still manufacture 11.75"? Raybestos? Other? I'm almost afraid to ask for Left Hand studs and expect I may have to transplant these myself. Any info would help before I switch to 10.98".

[Katfish]

11.75 wasn't available on E-bodies.
10.98 is factory

[moonshine_mike]

Thanks for the quick input.
Apparently I might need to look deeper. Checking the CHRYSLER MUSCLE CAR PARTS INTERCHANGE MANUAL 1968-1974 looks like the rotor should be 11.75" for 1970 only. I just checked the calipers on the car now which are single piston KH80012 which I assume are floating caliper in 1970 and sitting on what I thought were 11.75" rotors (cant easily measure). I assumed the rotors were 11.75" by looking up the 1970 plymouth service manual that lists these single piston calipers with 11.75".
Is it possible that these brakes I'm looking at incorrect for the 1970 E body Cuda?

[Katfish]

https://www.moparaction.com/2016/03/16/disc-main/

[cuda hunter]

Good article

[Brads70]

Make sure someone hasn't swapped out your spindles and caliper brackets for the bigger late model versions mentioned in the article.

[moonshine_mike]

Impossible for me to verify a previous potential swap and its always possible since I don't have full history. However, service manual as well as other published restoration books call for 11.75" not 10.98" until later year E bodies. Two of which I have added. Thus causing me confusion with what I am reading on the forum.

[Katfish]

Why don't you just take the wheel off and measure it?

[EV2RTSE]

Reading through this I was also already agreeing with what was already posted - rotors were originally 11", not 11 3/4" - and then just to make sure I went out to the garage and measured the two original 1970 two-piece rotors on the floor that came off of my car and they are indeed 11" and not 11 3/4".







 

[moonshine_mike]

OK, I removed the wheel on my disc brake 70 Cuda and measured the existing rotor size. It is an aftermarket one piece rotor and measures ~11". So at least I am no longer worried about replacing the rotors with a smaller size. My two other 70 Cudas have drum brakes. I also have a 73 Cuda of which I have removed the original two piece (hub/disc) rotors. I just measured these originals which are also ~11".
Further:
It seems clear that with a standard 14" wheel, only the ~11" rotor/caliper would physically fit as the 11.75" will have interference.
(The Article also mentioned this). That being said, my 1970 disc brake Cuda does have 15" wheels, which would have fit a 11.75" rotor.
But in all the options listings for the 1970 Cuda (I don't have broadcast sheets to check), I cannot find anyway of getting 11.75" rotors as an "extra" from the factory to add to the 15" wheels/tires.
So I am now estimating that 1970 Cuda came with only ~11" rotors even though I see multiple published documents stating that 11.75" rotors existed for them. (Latest one I read is "Challenger & Barracuda Restoration Guide")