you probably need to phase the rotor if you locked out the timing
http://www.msdignition.com/instructions/...RIBUTOR+pHASING

the rotor
http://www.summitracing.com/parts/MSD-84211/

somewher it says locked out may need phasing to use 20 deg retard
http://www.msdignition.com/instructions/Products/Distributors/84211.pdf?terms=84211