I built a few of the 62-63 Chevies , but with the 425 horse 409. I tried a "loaded 327", but the cars are pretty heavy. Even my Biscayne weighed 3760 pounds. I would recommend a 400 smallblock with a turbo 400, since you have a limited budget. It's almost a bolt-in, and has good torque to drag that weight around. Also it's easier on that 2-piece drive shaft and rear axle. You will need a positrac, or any serious "throttle work" will eventually do-in the rear axle.