I recently aquired a 1991 F-150 xlt lariat. Did the vehicle ever come with an option for the 302 v-8 motor? The previous owner said it had the 302, however it still appears to only have the I-6 motor.

 

Yes a 302 was optional.

 

The motor options would have been:
300 I6
302 V8
351 V8
460 V8

An I6 and a V8 look completely different, so it should be easy to tell them apart (as you seem to already know).

 

The 460 was not available in a F150.

 

The 8th character in the VIN denotes which engine the vehicle came with from the factory.

 

...looking under the hood is quicker than looking at the door jamb....

heh

t

 

And if you can't look under the hood, look under the truck.

 

if it's a 302 or 351, you should be abel to tell by the intake (large silver component the 2 black hoses to go from the airbox). It will say "Ford EFI" then have 5.0 or 5.8 stamped on it, people typically don't switch that piece in particular so its safe to say that what it says, is what is it