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flathead brakes


Supporting Member
Supporting Member
I am very close to ordering a T kit from Spirit. I hope to be running a 49-53 flathead engine. I am wondering whether to go with power or manual brakes. I think they will
be disc front and drum rear. If it makes any difference, I hope to be running a manual
trans. My main concern is the amount of vacuum the engine will provide for the power
booster. It would be great if someone is running both of these combinations and can
provide me with some first hand information, but I will welcome any input. I would perfer the power option.


If a hammer won't fix it, it's an electrical problem.
STD brakes are more than enough on these light cars.
I have a 2000 lb. T with 11" drums in the back and Wilwood 175 single piston calipers in the front. It has a vacuum assisted master cylinder.

I also have a 2200 lb. T with the same brakes as above and a manual master cylinder. Both setups stop the cars just fine.

I've never used anything but 40-48 Ford front brakes and various rear drum brakes with them, and no power assists. Cars literally stop on a dime. My one Son is running Wilwoods on the front and Ford drums on the rear, his stops even faster. My opinion is these cars don't need power boost, especially if you get your pedal ratio right.

Thanks for the great input. That is exactly what I needed to hear.
I think the Spirit Kit includes GM fronts. I am trying to decide whether
to go the 8.8" $200 optional Ford rear axle or just get the brakets
and use the 8" axle I have. I feel like the $200 is a little high as the
8.8" axles are plentiful, but could require more work to mount. I want
to run a Ford wheel lug pattern all the around.
Thanks again and I welcome any advice or experiences that might
apply to my plans.

Pedal ratio (10-12 to 1 is same as power brakes) and master cyl bore sizes, the smaller the Master bore, the more pressure you get, the larger the wheel cyl. bore the more pressure you get, so you can adjust to whatever you need...
I suppose it depends a bit on how you like the pedal to "feel". Matter of personal preference.
I like the pedal to come up hard after a very small travel which means low pedal ratio and low cylinder bore ratio = power assist.
If you don't mind a bit of pedal travel, then as Ted says, up the pedal ratio and the bore ratio and never mind the power assist. Same happy result.
Different strokes...........
Anyway, a healthy flathead pulls plenty of manifold vacuum if you gonna go that way.
I have a 61 Lark with 4 wheel manual drums and if they are adjusted properly, they stop fine. On a Bucket, power is overkill. Plus, it is more difficult to hide that booster.

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