double bumper heads? Boy it has been a long time. How about heads with double humps? Smile, you should hear some of the things that come out of my mouth.
You got the components to make it run except for the heads and a proper roller cam. Changing those per suggestions on this site already existing is the best way to go.
If you are a noise in the pants only fellow, use a Thumper cam. You will go slow but sound mean.