The Texas region SCCA web site covers road rally. See
www.texasscca.org.
Also, if you are serious about wanting to run in a Rally America performance event, read the rules first. Mostly because Ford is putting up some money for those who compete in Fords but I don't know what the restrictions are on allowable modifications. I do know that performance rally needs a serious roll cage. And that handling is more important than horsepower.