I am looking at fitting a HiFlow 75mm twin carb manifold to my 1600xflow in my Mk1.
The car currently has a non-boostered master cylinder attached directly to the firewall, but I have a boostered master cylinder on the standard brake extension bracket. 
The manifold seems to have a 30-35mm upward offset from head inlet port centreline to carb centreline.  Having read elsewhere that the brake bracket needs to be lowered, I am wondering if this is in ALL cases or just if there is no upward offset on the manifold.
So I guess my question is, what is the concensus?  Am I going to have to modify the brake bracket, or will I get away with it unmodified?
I should clarify engine is out of car and brake bracket is also, so unless I pretty much fully assemble I won't know for sure, and if it doesn't fit I will have to disassemble it all, all over again.  Just trying to avoid having to do it all twice.
Cheers for any thoughts.
Dave.

Well you could get it all in there then pull the booster bracket out if it fouls. I don't think there's a lot involved when lowering the bracket,. If anyone else can offer more info as it's something i have considered too. Sure seems cheaper than bias brakes, pedal boxs etc.  What type of carb are you using? 75mm twin sounds massive!

carbs are 40mm Dellortos.  Manifold is 75mm long.

i had a similar problem with my single 'swan necked' lynx manifold.
 
The way we tackled it?
Rotate the entire engine a little clockwise, to get the angles all working and correct amount of clearance (because the carbs will 'shake').
From memory didnt have to move the extended brake booster bracket at all.
 
my only comment is that you shouldnt rotate too far - otherwise you may have issues with your gearstick position.