Swapping in a big block

My scamp has the original 318 in it, it currently runs and drives. I really don't think I need rear discs on this car. I will run rear discs if I run an aftermarket rear, but if I can keep the stock rear. I just got the car today, I am not sure what rear is under it, I have not hada a chance to look. I have a set of ChassisWorks ladder bars and a S&W 10-point cage. The motor is a 383, std bore, 12.5 pistons, Eagle forged H-beam rods, ported and polished 906 heads, lunati valvetrain, it should be between 650 and 700 hp before the spray. The 727 is being built to hold the power. I am in the process of ordering an aluminum radiator. This is a drag-strip only car, I am going to strip the interior, gut everything and make it as light as possible. I am shooting for a low 10-sec ride. The cage will add some real stability to the chassis, the ladder bars will be tied to the rear attachment points of the cage. I just need to know what I need in the way of motor mounts. I had a 72 charger for this build, but I decided it was too rough to build and too heavy. I also didn't like the way it looked. I like the Scamp, it is unique enough that it will fly under the radar. So what do you think?