[eschaider]

I agree with you, Tom (W). I think it is a preproduction or early production version that was cut from a block of billet aluminum.

The giveaways are the near-identical, machined from billet, exterior shapes rather than the as-cast main body surfaces on the Holley piece.. Additionally, the throttle linkage is again a machined from billet item that was replaced with traditional Holley stamped steel components, as illustrated in the image on the Holley webpage.

The backside of the throttle body (facing the firewall) also appears to have the same fitting the production Holley piece uses.

My bet is that you have a prototype or early production piece that was made before the cast production pieces were available. I tend to like it better than the production piece!

BTW what ECU is used with this hardware for engine fueling?