>My old Aerostar had a 4.0 V6.  I believe it was an iron-block motor.  If it
>is, wouldn't that make it a bit heavy for a conversion?

My 83 Caravelle had a 174hp 3.8 Holedn (Aussie GM) V6 when I bought
it. Went well but cast-iron, heads & all, heavy. These vans aren't
supposed to be understeerers but mine sure was, and this may well
have been due to the heavy engine. Hence the impending change to SVX
power.