Is this the stock LM1 engine?
The cam in this engine is pretty lame, to swap heads means you want to swap the cam, otherwise you won't get the benefit of the head change.
Automatic trans? If so - 3.42 rear. Manual has the 3.08.
Now that I've further confused you - keep in mind the engine, if you want it to function correctly and for the way you want to drive, is a package.
I'll also suggest you pop into the high performance engine topics area on the www.nastyz28.com
message board. We all deal with the LM1 motor over there. Guys here are technically capable sure, but they have issues specific to late 60's V8's. The LM1 to a 1st Genner is a different beast than the LM1 you're asking about.
In summary, something I think is nice could be a complete waste of $ and effort for you.
If you go screwing with your cam, and you have an automatic - are you prepared to replace your torque converter? Next thing you know, you'll be broke and your car is all torn apart.
Spending other peoples $ is easy.
What type of budget do you have? You only want to do this once.
Go pop into the other place and search it, see how folks wake up the LM1 or radically modify it, and the implications of what changes they make.
(another example, any worthwhile mods will require ignition and fuel system upgrades).