Griggs website is acting funny right now.With there's you have to keep a shock tower but its really small maybe a inch or 2 under the hood.RRs is not the only strut set up but they don't handle as good to me as a car with a upper control arm.You can get a full frame from
http://www.gmachinechassis.com/ or
http://www.ajeracing.com/64-70Mustang.php and fatman fab has a couple and
http://www.seanhylandmotorsport.com/sema2007.shtml