Get Monster Truck after getting the stadium vends. Then get hospital, talk to Frink and restart the mission.

The strat here is pretty simple, you want to hit him fronthead and push him until you hit the wall, you may want to reverse and accelerate again to have him at full damage. Then reset your car to destroy him.

After destroying the car get the museum wasp, talk to Frink and get Longhorn back to get construction card.

This mission is done after 5-3. First restart the mission, then you want to nail Frink behind the Hospital sign.

Get museum wasp as a freebee after this mission.