Long story short, After rebuilding my engine that I had to go with the tall valve covers (roller rockers) I went to put in the alternator and it will not mount up as it hits the tall valve covers. Has any one else run into this? or have I done something wrong?

 

 

Not uncommon with the tall valve covers.  Sometimes installing a longer belt will do the job by itself.  If not, you may also need to get a longer alt adjusting slotted bracket to allow the longer belt.  I know they are available, but I'm not sure where at this point.  A bit of shopping may be in order.

There are some valve covers out there that are tall and clearanced for the altenator.  You have to love aftermarket parts.

Sources for new brackets off the top my head would be

March

Billet Specialities

Jones Racing Products

KRC

Concept One

Vintage Air

MR Gasket

TD Products

Another Option would be to remove the stock one and trace it out on a piece of flat steel stock making it slightly taller and longer on the slotted end then cutting it out on a metal band saw and deburring the edges.