If you want to talk weighs in a high performance or race vehicle you have to keep your eye on the bouncing ball and get away from shipping weights or web based crate engines--------
The FE is probably only about 30 lbs (or less) more than a Windsor based engine(I'm not talking 289/302)----the internal components will be almost identical in weights with comparable strokes------In fact the 427FE crank can be quite a bit lighter than your run of mill 351 4 inch stroker crank-------Pistons will vary some depending on CH and the dome/dish volumes but can be lightened in any case---wrist pins can be varied for any weight and rods will maybe vary 100 grams(only about 4 oz)
Oil pump, distributor will be equal, water pump/front coverfairly equal in aluminum----
The FE cylinder heads are some of the lightest anywhere and the alum ones will save 25 lbs per side--FE iron manifolds aren't even considered except on heavy duty trucks so won't look at a weight savings there except it will be a few pounds more than a 351w---
Starters and alternators will be equal and everyone should be using the new smaller compact sizes on either power plant
All this just comes down to there is a large following of the notion that the Windsor based 427 is a ton lighter than the 427 FE and it just isn't so--------