Master Cylinder Differences

[Runner 68]

Hello all. I have a friend that is fabricating adapter plates to use hydro boost for our Mopars. He's actually a Tri Five Chevy guy but has the intelligence to know Mopar guys will buy them too.
He's asking questions that are outside of my knowledge and pay grade.

1. Is there a difference in the MC bolt pattern in the firewall / reinforcement plate between the power booster and a manual master cylinder?
2. Did the MC bolt patterns change between years? (e.g. 62-67, 68-70, 71 and up, etc.)

Any input will be appreciated.

 

[Fran Blacker]

Put a 67 dual power MC on my 66 single power MC.

 

[R/T Boy 67]

MC bolt patterns are all the same during the muscle car Era. All firewalls will have holes for the master cyl. bolt pattern up until at least 74 ish. The manual brake stiffening plate for the model year should be used. The later 2 bolt aluminum masters are quite popular, so Making an adaptor for them on the outboard end of the hydro boost as well as the 4 hole wouldn't hurt.