[Wild83C10]

If you are getting blow bye you need a vacuum pump to pull pressure from the crank case. There are a few ways to go about this. You can spend $500+ on a belt driven vacuum pump/system or you can try an electric vacuum pump similar to what the mustang cobras run or you can see if a simple PCV system will work (closed valve cover breathers with a hose connected to a oil seperator then connect that to a port on the intake hose before the SC).

I imagine vortec should have included a BOV (blow-off-valve) but it doesn't appear they do. I would recommend a 50mm X02 BOV, they are cheap and they work. This should keep you SC happy and your carb. When the throttle blades close the SC is still spinning and building boost, but the boost has no where to go so it will try and exit from somewhere by pushing passed your throttle blades or other parts of your carb, it will also build up back pressure on the SC.

As far as a boost reference fuel pump or regulator it doesn't matter if it's a mustang or a chevy pickup. For every pound of boost you need more fuel. I would imagine you need a boost referenced pump or reg. Call vortec back and tell them you have a 351 cleveland in a 89 mustang with this SC setup and you want to know what fuel pump they recommend. Then just buy one that has similiar specs. Do you have an AFR guage? I highly recommend one.

Yes I would install some type of "cold air" setup.

If the engine runs cool and no over heating issues then I wouldn't change anything. Adding the thermostat was a good move, 180 is probably the best temp.

29" tall tire is a decent size tire and you may need 4.11, but I would drive the truck and run it at the track first before making any gear changes.