I would not recommend it. It will run, but the side with the F3TE head is going to flow more air, and fuel, and thus produce more power. This is assuming the heads and pistons are not altered from stock form to match. You would have to do quite a bit of work to get them to match. This is due to the larger valves and slightly bigger ports on the F3's. I'm sure it would run for a while, but would throw your crank out of balance. Sent from my iPad using IB AutoGroup
Thanks cbakker. That's what i was thinking but the guy who sold me heads said it would be fine. I ended up buying two e7's he had and have decided to pull the motor and replace both. Thanks for your help!
You don't need to pull the motor to replace them. It is easier, but not at all necessary. Consider having the heads looked at by somebody who regularly does headwork. The fuelie heads are pretty tough, but unless they are brand new, you have no idea if they were cooked on the previous motor.
If you do pull the motor, be sure to replace the front and rear mains while it is out.