I've been offered a 1969 318 engine and box from a Plymouth with about 40,000 miles on it.

I've been checking the net but can't find any info on whether the 1969 heads will be ok with unleaded.

Anyone know the answer, will they be ok or do I need inserts ?

thanks Steve  

Yes you will eventually need inserts for the valves will sink and sink...  

Plus if you continue to run them without installing harndened seats the exhaust seats will eventually crack which can leed to coolant leaking into the cylinders, not a good thing.  

Thanks for the quick replies.

Looks like a trip to the machine shop for the heads or do you know from what year unleaded heads were used on the 318.

Steve  

They were induction hardened around 73-74 and up. people ague this a lot so I'll say any thing after 73 is a sure shot.  

Thanks for your answers.

Steve