Slant six or v8 swap for use in a truck

If you are going to tow over about 4,000 lbs, you need trailer brakes. My race car and trailer are a little over 4,000 lbs and I have 4 wheel electric brakes. Wouldn't tow without them, the way people don't give you any stopping distance in front of you. Leave a gap, and some idiot will fill it. (then slam on their brakes).
PS: Don't forget the trailer breakaway brake system.
https://www.bing.com/shop/productpa...ds:"17963022736"&productpage=true&FORM=SHOPIC