Depends on the converter stall/flash as to which one will work better. your weight and gear is right on the cusp. The AG or RPM will make more torque below 4000 hands down but the M1 intake runners flow close to 290 (better than many Big Block single planes!) and the AG flows nowhere close to that....so up top there's no comparison in terms of peak HP potential...if you have the head flow to use its advantage.

I'm going to run both back to back on my little 341 but w/4.56's and 2800lbs I don't need a lot of torque off the line...that said I do prefer the AG's upper bottom so again it really depends on your flash. with 390 cubes I definately think the M1 has more HP potential. I run a 2" hvh super sucker on the M1 and that made a big improvement in throttle response. The AG/RPM responds very well to porting the 4 plenum transitions to each of its 2 runners, there's just not enough cross section there for big top end power as cast.

Edit: Going to alcohol may also be a factor, you'll meter a bit more fuel per HP so remember that the amount of fuel in suspension displaces the amount of total air you can get through the port. A bigger (and straighter) runner can be advantageous in that regard, especially in a long stroke motor that doesn't need a lot of runner length to make torque.

The M1 is basically the old Holley Strip dominator (slightly improved) and is on par with the Victor, the super victor is a step up on big motors with a lot of port or moderate size motors turning big 7800+ rpm.