I have a burnt exhaust valve or seat(low compression and popping from exhaust). Its a 72 F100 302 are the exhaust seats hardened? The guy from the machine shop said he thinks they are from 71+. But does any on know for sure? I am going to get them rebuilt and I am not sure if I need the seat or not. I would go aftermarket but I just don't have the cash flow right now.Thanks in advance
The machine shop is the one to ask. They can look at it and tell. And they should be able to hog it out and put an insert in if it can't be ground out good enough. If they don't know, find another machine shop.
If cash is tight and it's just a burned valve, don't worry about having your shop install hard seats. I've ran several sets of early 429/460 heads, some over over 40k miles, without hard seats on unleaded gas in severe usage and never had a problem. It's extra insurance and I'd do it if I was restoring something I intended to keep forever.