Good thing you used steel valve covers, sometimes cast valvecovers have clearance issues on the heater motor(We removed the heater assembly in our two street cars). Ig your gonna have to buy a diff booster have you considered converting to manual brakes, we have them on our 67 gt and it runs high 10s 440/auto and havent had any issues. But on that car we just converted the rear to wilwood disks(I'll do a post with pics i took during the install.) and we are now doing the rest of that brake swap under the hood.
Good luck,
Jr.
