I have a Procharger F3M (same as a F3-121), and a F3-130. Both head units are brand new, never used. I took them in on trade for a F1R and F1X. The F3-121 is reverse rotation, and the F3-130 is standard rotation. I do have the crank drive main bracket to mount the F3-121 to a SBC, and the F3-130 will need to be gear driven. Both are in perfect condition.