I have a 460 in a 68 stang and I have the same valve covers as you do.I had to convert to manual brakes also.Its really not that bad as long as you have the right master and a manual brake pedal.I tried it with the power pedal and the pedal was like a rock! I changed it and was much better.I wouldnt have enough vac anyway for power brakes.My headers are from total performance but I used the crites engine and tranny mounts.The 2" headers fit good except the #8 tube hits the steering box which pretty much clearanced itsself.Hope this helps.
Bob
[addsig]