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I have a 67 valiant dedicated drag car. I installed strange front discs and kept the rear drums. The new master cylinder and after market porp valve are going in now. Should the prop valve be on the rear or front brakes and why?
4.50s in the front, 10.50s in the rear 11s et.

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Put it on the fronts... with skinny fronts and big
rear tires you want to keep the fronts from locking
up on a spike of the pedal

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on the other side of the coin i've watched rears locking up with too much rear bias. my prop valve which did serve the fronts now serves the rears. to me, it feels more stable than it did before.

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It takes very little effort to lock up a set of skinny
fronts and it doesnt take alot of skidding to have them
blow out.... yes I can lock up the rears but it takes
a pretty big spike on the pedal

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Mine is installed on the rear circuit. It’s been that way for years with no problems. But what Mike said about the installing on the front circuit makes sense.

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One other thing when you install it on the fronts...
if you lock up the fronts... you dont have steering
while locked.... to me its always been a physics thing...
you have 2 or 3 times the tire width over stock(even
more) which can do MUCH MORE braking VS a much
skinnier tire.... most guys will hit the pedal pretty
hard on the top end to keep from a break out and
can lock the fronts without the prop valve on them...
Also if you notice that our race cars dont get the
front end dive to them (due to the springs) like a
street car with a nice ride rate... so we dont get the
70% front braking like a street car...
also a adjustable prop valve is nothing more than a
orifice to SLOW the fluid flow... given enough time
it will match the other pressure(based on the orifice
size its set at)

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Mine is installed on the rear circuit. It’s been that way for years with no problems. But what Mike said about the installing on the front circuit makes sense.

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One other thing when you install it on the fronts...
if you lock up the fronts... you dont have steering
while locked.... to me its always been a physics thing...
you have 2 or 3 times the tire width over stock(even
more) which can do MUCH MORE braking VS a much
skinnier tire.... most guys will hit the pedal pretty
hard on the top end to keep from a break out and
can lock the fronts without the prop valve on them...
Also if you notice that our race cars dont get the
front end dive to them (due to the springs) like a
street car with a nice ride rate... so we dont get the
70% front braking like a street car...
also a adjustable prop valve is nothing more than a
orifice to SLOW the fluid flow... given enough time
it will match the other pressure(based on the orifice
size its set at)

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I wonder is lack of "dive" you mentioned is caused by what?

And a skinny tire half the width of a rear tire will have more traction then the wider rear tire if it has twice the weight (say from weight transfer, and the fact it is not linaer )

And the need for steering becomes pretty useless when a locked rear end tries to swap ends.

I say there is not cut dry method, he should test under controled conditions for what the driver and the car needs.

I am puzzled as in situation an experienced driver in a properly biased set-up would keep fronts locked long enough to blow out other then a panic situation.

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I wonder is lack of "dive" you mentioned is caused by what?

And a skinny tire half the width of a rear tire will have more traction then the wider rear tire if it has twice the weight (say from weight transfer, and the fact it is not linaer )

And the need for steering becomes pretty useless when a locked rear end tries to swap ends.

I say there is not cut dry method, he should test under controled conditions for what the driver and the car needs.

I am puzzled as in situation an experienced driver in a properly biased set-up would keep fronts locked long enough to blow out other then a panic situation.

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Mount your front tires on the rear and tell me which
has greater traction... yes it does have twice the
weight per sq in but the rears have MANY times the
sq inces... as for a person holding the fronts long
enough to blow them... they dont know they're locked up...
do it what ever way you like

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Catalog says rear for street, front for race. Guess I will go front for the start. Thanks for all the knowledge. Plan to mount right before the line lock.