Brake Booster confirmation.

StrokedBird

Member
Jun 19, 2021
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So.......... on my 1985 Thunderbird Fox I am preparing to swap out the Vacuum Brake Booster to a smaller diameter unit (running a 351W motor and need more valve cover clearance), so I need to confirm that the '93 Cobra Booster, which is smaller diameter but a little longer, is the correct booster. Correct? I've also read that widening the mounting holes on the firewall will allow easier installation. I would love to run the Hydroboost system but for this application I believe the Vacuum unit will be adequate since I'm not running a bunch of lift or duration on the cam. TIA
 
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The 93 cobra unit is roughly 220 in diameter.

The standard 87-93 booster is smaller in diameter. I believe its 190mm in diameter and Dual diaphragm

The early single diaphragm units are 220mm
 
Just for reference I installed a 93 Cobra booster on my 93 fox with a stroked 351w ( 393 ).
Had to clearance the shock tower with a 3lb sledge a little more than I was expecting but
it's doable . That and a lot of cussing of coarse.

Not sure what the difference for you will be given it's going in Tbird but thought I would mention it.