Sounds like your friend was already committed to a rebuild or certainly far more than the OP, with a cam and checking the crank. Once you'r that far, and you have the budget, going the rest of the way is a no brainer.

Building the ideal motor is simple, especially when it is someone else's money.

But there is such a large gap between doing heads verses doing a motor. If he does heads, it will be a marked and noticeable improvement from where he is now, he can do it in a weekend, and can easily get out of the whole deal from beginning to end between $1,500 and $2,000. Once you say the word "pistons", from the beginning to the rolling down the road complete, it will be $8,000+ and at least 6 months.