What are the plans for the truck Street? Race only or both?
The Hedman mount kit works just fine, the headers is going to depend on what you are doing with it. If you put long tube headers on it they have to come apart just to change the oil or work on the starter. The oil change tuns into an hour and a half job. If race only fenderwell is the only way to go. Street mostly I'd put shorty's on it. Make sure and use a rubber transmission mount too.