Correct Tire Pressure ?

The tires on my 72 vette are a P225-70 R15. These are Goodyear Eagle GTII. I don't think this size is the stock size that came on my vette new so does anyone know what tire pressure I should run these at? I e-mailed Goodyear but they told me to look in manufacturer book but this size is not listed.

 That should be the stock size. It is on my 73. I have P255/60R15 on it , I run 28 PSI. The door sticker says 20 PSI. Some guys on the site do run 20 PSI with no problems.

[QUOTE=Lynne73]

 That should be the stock size. It is on my 73. I have P255/60R15 on it , I run 28 PSI. The door sticker says 20 PSI. Some guys on the site do run 20 PSI with no problems.

[/QUOTE]   If you inflate to 28 psi with the 60R should I inflate to 30 psi with the 70R tire?

I have the same size GT IIs on my 76 ( 3+ years) and have always run around  30 - 32 psi w/o any problems.  My guess is mine will probably dry rot or I'll want something different before they wear out anyway so I just try to keep to a number I can remember easily.