What size radiator cap do you run?

[edspaged2]

I have read up on articles posted on the net that early mustangs were originally equipped with 7psi rad caps. Is this true for both 6 and 8? Or higher depending on engine size? I have a 13psi cap but feel that the pressure is a bit high. I have a bone stock 302w. I'm aware that the higher the pressure the higher the boiling point. So why do most people tend to go higher than what ford recommended? Wouldn't this add extra strain to your cooling system? Higher chance of hose blowout? Water pump seals, etc.
What size caps are you guys running?
Cheers
Ed

[GLENN 70]

13 lbs is fine,no problems with blowouts,higher pressure caps will stop radiator getting steam into it like a low pressure cap will by stopping it boiling and releasing pressure and allowing air into ratiator and then into steam .Early mustangs had over heating problems from this and ratiators were too small and most did not run a shroud .

[BLKPNY]

It is the old heater core that will suffer from the higher pressure cap. I run 15lb's on mine, and the new car will be similar, if not 16lb. The new car will have a new core anyway, but if your core starts to leak, it needed changing anyway.
I definitely would not be running anything less than 13lb's on anything, and I would be running the minimum concentration of coolant, to aid cooling, ie: 33% Coolant concentrate with a 13-15lb cap.