Szilagyi writes up more than 6 Mopar SB engine combo’s including several that mix LA and Magnum parts.

Szilagyi writes in several of these combos that engine balancing must be done but “almost never” is expensive “mallory metal slugs” required.

Find a shop that has done this before and get a up to date $ quote.
Inflation has got our attention and the $ estimation Szilagyi gives in 2005 for each combo seems “real low” to me.

For example he lists $150 for crank balancing on a
Speed O Motive 390 cubic inch V8 with year 2005 “approximate total engine kit price” of $1550