"This is a fairly acurate statement. And people who insist on useing old outdated openchamber iron heads will always be saddled with this. Why for the differance in price would any one use regular old J heads X heads or something when you can use a magnum style head for only a tad more. Same with pistons. Why leave 50-75 lbs of tq on the table since you need heads and pistons any how? And a good combo of KB 107 pistons and magnum heads can easily add that over stock low comp 360 pistons and open chamber heads. Plus you will get better miledge so why saddle him with old information? My first engine that was anything not totally stock was a 360 KB 107 combo with 302 heads that I heavily ported lightly milled and ran in my 68 dart. The only problem I had with detonation was the fact I left very sharp corners on the pointy thing in the middle of the chamber, I had to pull the head back off grind that thing down and it was fine. The magnum don't have that thing and has a way better chamber so he should be more than safe.

Also someone mentioned putting a carb intake on a JY 5.9 that is a good idea as far as simplicity goes. It will make more power than the 300 hp crate motor because the stock cams are actually bigger than the 300 hp cam. Also of interest is how those 300 crate motors always seem to make more than 300hp even with 318 manifolds. People never give the magnum heads the credit they are really due". WOW thats good info I now have my soft drink running out of my nose. Thanks alot.

All kinds of info here. What's in my truck is an 87 360, with 80K miles. It has an XE262, performer (small port 318/360), factory original 308 heads with matching springs, cheap headers, and an Edelbrock 750 AFB. Basic, easy, pulls from idle, runs on 87, I dont ever see the high side of 4500, nevermind 5+, and it will spin the 31s w/4.10s all thru first gear. With a running engine to start with, I think all of it cost me about $900. That's what i'd do. It's a truck. It needs torque, and mileage.