I would think that running any reasonable boost would be fine with blacktop rods, this is because the killer of rods in a 4a engine is revs not compressive load. The reason why this is so is because on the compression stroke the inertial load of the piston and rod counteracts the compressive force. There is some bending force at a reasonable amount of the point of 90 degree on the downstroke. Long story short keep the revs at 8000 and you will be fine, cheap upgrade with silver-top rods that will have a block break before they do or lastly the after-market rods which are better suited to atmo engines in my personal opinion.