It sounds like your 848 head is pretty close to being a boat anchor. Drop me a PM and I'll respond with a phone number. There's a few tricks involved in increasing the compression of the early head to make it pretty much equivalent to an 848, but it's best discussed in a 2-way conversation, not with a keyboard. That's what the hotrodders did before 848's became generally available in salvage yard
.
Anybody with a lathe and a micrometer can make his own bronze valve guides, but why bother? Thin wall bronze guide liners are cheap, plentiful, and easy to install. I'll be doing that to a 216 head in the next few days.
Jerry
