I want to swap out the blown 302 in my 1991 f-150 with an overdrive automatic tranny with an in-line 6 from a 1988 150. Can I do this and keep the automatic tranny or will I also need to switch to the 4 speed that is with the 6?

 

The bolt pattern is the same. You can use either transmission.

 

Get a flexplate for the 300. Do not use the one from the 302. They are balanced differently.

 

I heard that flexplate diameter is different between the two motors. If so will the starter position from the 302 tranny work with the new plate?

 

300 and 302 flexplates are the same except for the weight welded on for the 302.