Bill,
If it's a SBF, that combo works using the stock MSD Pro Billet Distributor, 8578 for 351W, or 8579 for 289-302. It gives you just enough clearance (with fuel pressure regulator overhead) to be able to remove/replace the cap & rotor.
Do you need the Holley because you are going sequential? FAST also makes a Dual Sync Distributor but it could be the same as the Holley. I just haven't compared them side to side.
Borla sells throttle body extensions, but I believe are made to extend the length of the air horn above the throttle body, and are not machined for O-ring seals. BTW, buying 8 of those would cost you about $100 more than just getting the MSD distributor...