does he maintenance the car regularly(plugs, fuel filter, dizzy)? Does it idle/run correctly otherwise? Any aftermarket stuff (fuel rail, fpr)? It's not getting one of 3 things air,fuel,spark (I'd look more into the first two). Perhaps the fuel pump/fpr is going bad..... I'd check for vacuum leaks first, they always seem to be the gremlin when something isn't running quite right. Just some ideas.....

I'd like to help w/ the swap when you get around to it...