I'd go with the Magnum just because I had one and it was a great engine. Actually I had a few issues with my Magnum. I started out with the 300 HP version and blew an oil line to my oil filter relocation kit and gutted the bottom end. I then replaced the short block with one of the Mopar Performance 11.5 to 1 short block assemblies.
Turns out they did some bad machine work on the deck and it had 11 to 1 compression on one side and something like 12.3 to one on the other. It busted a piston into what looked like pie slices with only the rings holding it together in the bore. I called the tech line and raised hell and they sent me a new short block assembly. This one ran like nobody's business. 11.5 to 1 compression with mild timing and an MSD 6AL on 93 octane gas. It would push my '72 Charger with 2.76s to over 160 MPH, verified by police radar (don't ask).
Oh, I did have a single plane intake on the Magnum also. I started out with the dual plane that came with the 300 HP Magnum but when not paying attention to what I was doing and I was putting the intake on after the first short block swap, I followed the torque specs listed in the Magnum Engines manual to the letter and promptly busted the intake. Seems there was a misprint in the manual and I just ran with it, lol. When I called and raised hell about that, they agreed to send me a new intake and since they were both the same price, I asked for the single plane intake and they agreed.
My Magnum engine started out real bad. Right after installing it I gutted the 904 that I had intended to last at least a month while my 727 was being built, then the fiasco with the oil line and then the intake and finally the busted piston episode. After it was all said and done, it became one of the best engines I've ever had.
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