HO 5.0 Question

The HO wasn't available in the Grand Marquis. The only engine options were 140hp 5.0 single exhaust
150hp 5.0 dual exhaust
or a carbed 5.8L

Some guys 'convert' them to HO's, check the throttle body, the SO has a 52mm? T/B.

Differences in the SO vs HO

very slightly dished cast pistons with NO valve reliefs(any cam over a standard H.O. would be asking for P/V issues)
14lb injectors(black)
E6 heads(86-91)
Upper intake is different(lower is the same as H.O.)
Different firing order/cam
86+ are roller blocks but not neccesarily roller motors.
T/B is much smaller
Speed density
Nylon toothed Timing chain set
Forward rotation waterpump
EGR spacer is tiny and can safely be bored to 62-63mm tops.
Oooo and those lovely cast iron exhaust manifolds.