GTD brake upgrades

Hi, I own the very first GTD. I see various discussions about brake upgrades within 15" rims but can anyone tell me what GTD used over time on the original hubs/uprights supplied? What are the original (tiny) brakes on my car? Escort? Many people go to Willwood but I am sure even the regular available upgrades using road based calipers and discs was a big step forward at the time. My second question was if anyone has done drawings for side intrusion bars built into the doors for the GTD.
Hi Aaron Mike is right about Granada uprights and discs on the front but I was wondering if you mean the first GTD with their own chassis or the first GT40 they did? They started off converting early KVAs using their own sub frames, again using Granada brakes all around, discs on the front and drums on the back. They might even have dabbled with the idea of doing 40s earlier than that but I don't know any more.
Aaron, don't think of upgrading front brakes in isolation to the whole braking system, and ( my opinion ) don't think Willwood ! First consideration is change the pedal assembly for higher ratio , I use Tilton overhung units. then whether you wish to use servo assisted brakes or not , can you achieve sufficient vacuum from the engine or need independent vacuum pump set up, and then consider the brakes as a hole to get the correct balance on the car. I have found that AP brakes, 4 pots same size all round, works best for fast road and track, but you must assess what works for you and your potential use of the car.
Might also consider hispec brakes from UK (
Not able to post links yet but they have bolt on kits for Granada that fits inside 15in wheels.
Thanks everyone. I agree that the system in its entirety needs to be worked on, didn't really think about pedal assembly though. It's a job for an expert but I don't like to reinvent the wheel. If there is a good package that is tried and tested I am always happy to replicate that. I was mostly curious as to the disc diameter that will fit, which seems to be 11.5 - 11.75" depending on caliper depth. Modern calipers have more streamlined profile. I have Willwoods on my RCR XJ13 replica but I would say that AP would be generally a superior product. Kev, I think mine was the first car GTD did as a complete build themselves.