I have a 84 f-250 with a built 302 in it. I know too little motor for to much truck. But I was told by switching the c6 I currently have in there to an e40d this will give me way better take off and better cruising speed. Is this true and what vehicle would I want to get it out of so it dont give me any headaches?

 

An e4od is going to be a headache not matter what vehicle you get it from. It's fully electronic and requires a computer to operate it.

I would keep the c6 and change your rearend gears. If your engine is modified very much, the overdrive will take it out of it's powerband and it will be a dog on the highway.