building a mild Daily driver 318
Machine work varies by location. I just had my Ford 400 heads rebuilt and they were not quite 400 for everything they did. There was no guide work involved, because they were in great shape. In fact, the heads had been already rebuilt and new exhaust guides were installed. The intakes were perfect. However, the heads needed exhaust seats badly, as a few of them were sunk. So, I took them in to get them right. They installed 8 tungsten carbide exhaust seats, milled them .060" and set my valve springs up on them. Had they needed guide work, I could have added another 200 dollars.
It might be to your benefit to check out Allied Cylinder head. They offer reman castings very reasonably. I actually went that route last year, when I replaced the heads on the 351M that is in my truck now. The heads were worn slap out. One burned exhaust valve, they needed all guides and all exhaust valves, plus all exhaust seats. That would have cost a fortune. I got a pair of reman heads for 350 shipped.
I could have done that this time, but these particular heads have better ports and chambers and are hard to find, so I had them re-done.