I was reading a jegs magazine and i come up trans brakes, what are they and what are their purpose in the tranny, i got a 700r4

 

Purpose is to allow a really hard launch at higher rpms where most drag cars make power.

 

They shift the trans into 2 gears at the same time, which thereby locks it up solid. 1st and some other gear (usually reverse but it varies with trans model) To launch, it lets off the other gear. It allows you to fully load the motor into the converter without burning anything up except the fluid, and then lets it take off without shifting into a gear to do so.

 

so they are not meant for stock l98s

 

The motor isn't as important as the trans, converter, rear gear, tires, and rear suspension setup. If you have a stock motor backed by a built trans with a high stall converter hooked to a built rear with slicks and a tuned suspension then you could very well need a trans brake on a stock motor to get the most out of the car.

A trans brake is like dumping the clutch on a stick car.

 

in otherwords, you're going to have to work to make it hook and make it so it wont blow apart the rear end before its going to really help.

 

To add to it You say you have a 700R4.... Ive never even seen a Transbrake for a 700r4... I would not like the chances of a 700r4 holding up with a transbrake even if they did make one...