My inline has been rebuilt with all new internal parts except the crank shaft. I put a torky cam in it and a 390 Holly with an clifford intake and hedman headers with true duel exhaust system with EdleBrock stainless steel 304 series mufflers. All sounds good at idle. When I accelerate it sounds like a cheap 4 cylinder inport. HELP!

 

Well I think if you were expecting it to sound like a V8 you had the wrong expectations. I wish we could make them sound as good as a V8 or better, but still have it's own unique sound. The exhaust companies need to get on that.

The best you can hope for is a great sounding idle, and good sound until about 2000 RPM or so. My truck has a bad leak in the front under the cab, and it still sounds better than any fart can 4 cylinder at all RPMs. I noticed some 300's sound like diesels if thats your thing you can see what needs to be done to get that sound.

I suggest you watch youtube video's and go to the inline 6 forum below, exhaust sound clips is the very first thread at the top of that page. Listen to all those and see if your 300 sounds similar to what other members' 300's sound like. It may be you just don't like the 300 sound at all, and it may be your exhaust set up itself.