Scorpion Racing Products offers Narrow Body Race Series and Narrow Body Self-Aligning Race Series rocker arms in 1.5, 1.6 and 1.7 ratios and in 1.6/1.5 ratio sets (all with a 3/8 stud) that were designed for use with center bolt valve covers.

You will still have to check for pushrod to cylinder head clearance and for interference upon installation as there were many different covers produced with different internal baffling. You may have to do some minor modifications to the baffles.