I want to change the two piece valves for the solid ones. What are the odds that when I take the head off it's warped? Also do the head bolts break easily when trying to remove?
What are the chances are that it's not? You will not know till you have it off and check it.
Yes you can snap off the head bolts. Don't strong arm the wrench, don't use a cheater bar. Take is slow and steady.
Maybe some PB Blaster?
Kroil is my friend to help loosen parts.
It's very rare to break Model T head bolts when loosening them - it's when tightening them too tight they can break..
Original cast iron heads are rarely warped, while high compression aluminum heads might.. But that's fixable, just like broken bolts - it's just another inconvenience on the road to a better running and more reliable T
Use air impact wrench on low setting to jar loose
A couple of years ago I pulled the head on my T just for a looksee. I have no reason to believe that it had been off previously. I had no problem with the head bolts. I did replace a couple of them because I didn't like the look of their threads.
Mr Frugal Finishes First!
If your head is not leaking, it probable is fine. A head being warped has never been a problem, just bolt it back on and presto it is un-warped. If it has some sort of deterioration on the sealing surfaces,then there is problem. Now lets think about an over head cam setup that is warped ,if you should mill the head flat, think of what it would do to the alignment of the cam shaft. If you put a head on some blocks at each end and use a dial indicator to check deflection, just standing in the middle of it will deflect it, so how much weight are you adding by bolting it down . MOST HEADS DON'T NEED TO BE MILLED BECAUSE OF WARP-AGE. My brother had a Honda with a warped head (over heated horribly) Of course no money for machine work or exchange. You couldn't move the camshaft freely, I re-installed it with a new gasket and all was well. Just saying