Originally Posted by hatemakings/n
I was thinking about doing that same swap when I did my rebuild. Cost wise it depends on what you want to do. I was looking at a mild compression forged piston and ring set, edelbrock alum heads, rpm intake, crane cam, Holley 750, all MSD ignition. Cost was about the same over all for those things. Heads are more for 460 but 390 intake is more then 460 intake. Cams about the same either way. Carb is the same. Dizzy pretty hard to base a decision like this on a dizzy. Machine work plays a minor role also. How much machining does either engine need? I went with the 390 build. Mainly because I didn't want to pay the extra cost of the motor mounts, headers and other stuf needed just for the swap. I spent alot of money (for me anyway) to get the 390 to where it is. The same money in a 460 would have me running circles around this 390. Anyone can put a 460 under their hood and make it go fast. It's unique to do it to a 390. I always have someone come up and ask "Is that a 460?" I love the look on their face when I tell them it's a 390. Just my $.02
My vote is for the 390
Made both 390s, 427s and 428s go very fast. Have also made 390s and 428s get respectable gas milage and pulling power. Done the same with 460s too. The statement "Anyone can put a 460 under their hood and make it go fast. It's unique to do it to a 390. It's unique to do it to a 390. " is BS. A good running 390 was the norm years ago and is IMHO the same today. I've seen guys screw up a good engine rebuild by putting the wrong intake system on it. Stock truck 460's will out torque a stock 390's, but the 460 isn't happy above 4500 rpms any more than a stock truck 390 is. Unless you swap the cam in the 460 stay with a 600 cfm just like you would with a 390.