Exhaust question

I'm not quite sure if this is the right place to put this thread, but here goes. I drive a 1997 Ford F-150. It's got the supercab and the longbed, and that cool looking XLT under the name. However, none of that is relevant.

I recently removed the muffler and put in a straight pipe. It sounds like a truck now. However, my grandpa threw a fit. He said it sounded like crap, and that it's not going to run right now. Something about back pressure. I've had other people say the same thing about backpressure being needed.

So my question is this: Is it really going to hurt my truck to have a straight pipe on it? As far as back pressure goes, and gas mileage? Wouldn't the catolytic (SP?) convertor provide the necessary backpressure? Also, when putting the straight pipe on, I used inserts in the pipe that were flared on end, and smaller on the other end. The exhaust is a 2 1/2" - 3" pipe, and the insert I have inside the pipe has a part that is only 1 1/2" in diameter. OD or ID, I can't remember.

Most amazing jew boots

Can a mod correct my thread title? I don't know why I mispelled exhaust.

There's nowhere I can't reach.

Well, actually, it is still quieter than my g/f's father's GMC. He's got a 5.7 L V8 with twin straight pipes compared to my 4.7 L V8 with the single pipe. I've driven right next to police, and I can still drive in at night and my grandfather doesn't hear me coming.

However, it seems you've answered my question. Thanks.

How ya doing, buddy?