My 68 Cougar has stock power disc brakes. Headlights are also vacuum operated. For my 427 build I'm looking at a heavy duty electric vacuum pump from Master Power Brakes. www.mpbrakes.com it'll hold a constant 18-20" of vacuum. $345 part # AC2724K. My cam is the old NOS solid "D" grind .600/.330. There are also vacuum canisters at Jegs/Summit for under $100 that might be ok for your app. And vac pumps you can buy to run off the engine but are a bit costly. I often wondered if a stock smog pump might be a plausable solution. No idea there really just thinking out loud. My 86 GN had the Powermaster system and yes they were expensive to replace. GM units rebuilt were like $800 years ago IIRC. My 67 GT500 came with a aftermarket set of those same MT valve covers. They fit fine on the 428 and clearance around the booster was ok. If your using the stock 3 pc factory motor mount the stock block plate only needs the top hole drilled in the block plate for the earlier 2 bolt blocks. No spacer plate needed. So be sure you have the all correct FE mounts for the Mustang/Cougar. Mansfield Mustang sells everything and has pics onsite to compare yours with. Think Mustangs Unlimited too. www.mansfieldmustang.com