What head casting should I have, I have searched with mixed results. Seems as though they should be the e6 head with flattop pistons correct?

 

Look at the lower front corner of the passenger head next to the valve cover. There should be a letter cast there. E6's have an "S" here. E7TE's have a "T" in this location. If there's no letter then they're earlier heads. GT40's have "GT" here or GTP on the P heads. Same thing on the lower rear on the driver's side head.

 

I know the engine coulda been swapped at some point but I doubt it. I was wondering what head should be on an 86 302 efi.

 

Most likely the E5 heads. But could be E6. You can mill those GT40 heads .040 and pick up a half point in the ratio. Best head gaskets to use are the stock expanded graphite gaskets, Felpro 9333. I use these with my Canfield aluminum heads, liberally coated with Kopper Kote spray.

 

As of right now its not in the budget for a head swap I was just curious as there seemed to be no set answer.

 

That is because these trucks were dumping grounds for all kinds of parts that Ford was trying to use up including engines and engine components. Technically the E6SE car head should never be found in a truck but for whatever reason the low-po 5.0 Crown Vic motors found their way into trucks anyway.

 

Gotcha, Thanks guys...