Cast iron valve guides or bronze liners

[CDXXVII]

My machinist (not an FE expert) prefers the cast iron guides. My iron 427 LR heads currently have thin wall bronze guide liners that are worn. I kind of like the idea of just replacing the liners without boring much from the original head.
Is there any risk in using the larger OD iron guide instead?

[hotrodfeguy]

I tend to look at guides like cams everyone has a preferance. I like the old iron myself , second the thin wall bronze and thermal expansion is less. as with a thick bronze guide it can swell up on turbo/supercharged applications. Unless you allow for an extra .001 or 2