Tires: tire pressure, tire guides, g20 van

Question
i have a '86 g20 van. the problem is that there is no placard on the door to tell me what the pressure should be. (no owners manual ether.) where should i look to know what pressure i want? can you give me any good faith advice on how to deal with this?

Answer
J,

See if this makes sense:

Tire Guides lists 2 possible tire sizes:  

For the Regular G20:  P225/75R15 inflated to 35 psi front and rear

For the G20 with the LH6 option (I wonder what that is?)  P235/75R15 inflated to 35 psi front and rear,

According to Tire Guides, this is valid for model years 1983 thru 1989.