[77 Sprint]

I'm new to the world of Pontiacs, dealing mostly with Chevys and Dodges in the past but I found a really clean 1977 Pontiac Ventura Sprint and had to have it. The car is in great shape but has no engine or tranny onboard. I have the Shaker Hood scoop laying in the front seat. My Question to all you purests out there is what belongs under the hood of this fine looking Ventura? I was told that the last owener of the car had a 455 in it and was drag racing with it. This might just be true because the rearend spiders are welded and will have to be replaced. There certenly looks to be enough room for the big block but was that an engine option for this car? The end result I am looking for is a correct car and engine combo that will maybee give those Ford 5 point slow boy's a run for their Money. Any comments on the sugject would be great. Thanks.