I am just finishing up my 383 into a 67 barracuda. I would strongly suggest that you do not use the headman headers. Spend $1000 on the correct ones and you’ll be far ahead in the end .
Well, I didn't feel bad about putting a few dings (and only a few) in a $200 pair of headers but certainly would have been pissed to do the same thing to a $1000 pair. You will also be $800 behind that could have been spent somewhere else... In the end, it's your build, your money, your choices :)
motor plates are a solid mount but work wonders for custom header room.
Not necessarily. I used an AR Engineering plate, but made mounts from a pair of poly strut rod bushings and some angle iron. Basically like the BBD elephant ears mounts but using the motor plate. Make Your Own Elephant Ears Page 4 - Finished Product