Which heads to get?

To be a good match, I agree.
I'm running a 27 inch tires, 4.10/4spd with a [email protected] cam. I could use more gear. But it isn't like it is in liveable. The lower the gear the longer you wait to get into the power band to get going.

There is a wide bracket in which any cam can operate in and work well. Going beyond that can cause issues with the engines operation. Or how well it operates. (This is how Edelbrock came up with there matched power packages. A great gimmick that makes sense.)

To much compression, 12-1, with a RV cam, like a [email protected] will require an octane of way to much for a street driver and most wallets. On the flip side, a 7.5-1 ratio and a nice drags cam of let's say, [email protected] makes the engine feel like garbage. These two examples show a gross mis match of parts put together outside of there operating perameters. You want to balance the whole package.

With 3.73 gears, the expected "Performance" engine package would expect to see a cams range in a certain bracketed rpm range. It is more of a waste to use a cam like [email protected] with these tears and actually expect a great performing engine. Like wise, a cam of [email protected]+ would also be on the outside of the bracket. This doesn't mean it can not be used but the effective and balanced package will not go outside the bracket of best suited parts to use for it.

It's all about the balance of the engine for its intended usage.