New heads/intake/rear end

My opinions.. short and sweet...sort of...lol
You wont break an 8 3/4 and there aint no way to get a dana60 in and running under your car for $1500 unless someone gives you one ready to bolt in.

The heads... irons are YOUR best bet, but do not compare to aluminum. Iron is the best you have when someone that limits the class or personal choice. No other build (when budget is considered and planned for) should use iron heads any more. RPMs would be my choice for what you have, and what you want in the future from this block.

The intakes.. the RPM would still be my first choice until you either cam it or convertor/gear it to work over 6K. The M1 is a good all around single plane, but does sacrifice the flat torque curve for higher peaks and higher peak rpms. The Victor is made with a larger runner volume. So they say it's better for higher rpms where the runners will aid the cylinder fill. They figure it for the 3.31 stroke tho. 360 is 3.58... so it will work better, but is nothing near what you need. I use the Victor for 4" stroke engines that can use it. The M1 for snotty mid-size engines.