Lincoln Pimpin'
Active LVC Member
'91 and early '92 models have the 'bastard block' 4.6 w/ AOD transmission bellhousing and 2 bolt starter. Nothing particularly wrong with this if you are just using the car stock but if you plan on ANY performance modifications you're better off starting with at least a '92.5- (and much preferably a '96-)
1995 and older 4.6l 2vs are prone to valve stem seal seepage which causes excessive oil consumption and the infamous blue smoke puff from the exhaust at stoplights. -'95s are also prone to clogging EGR channels which will throw a CEL for insufficient EGR flow.
'96- models don't have the valve stem or EGR issues of the -'95s, however if they still have their original composite front coolant crossover it is prone to bursting. There was a recall on this however any of the vehicles effected are now out of the extended warranty of the part. It's not a difficult repair, though. The new manifold kit will run you ~$200 aftermarket.
'95- (-'02) have an improved front suspension and steering linkage for better on center feel and handling. '97- even better steering response thanks to revisions to the steering gear and '98- have the watts linkage rear suspension.
If you experience torque converter shudder with any '92.5+ Town Car (AODE and successors) drain and flush the ATF with fresh Mercon V fluid.
Also, the o-ring seal on the 1-2 accumulator piston on -'96s wears out (often causing delayed and/or harsh 1-2 engagement) and the aluminum accumulator can scratch the bore. Common issue, easy fix.
Info: http://www.p71interceptor.com/tranny/accumulators/partnumbers.html
Didn't the 91 and before have the 5.0?