I am looking for the air plenum throttle body for a 1969 engine because I am looking to pull the vacuum for timing control as it was done before the pollution control setup that changed to a constant vacuum setup in 1970.

Thanks
Brad 615-406-7052

bc:

Do you know if the same casting was used for both versions of the throttle body, with different drillings for each? If so, and you have the later version, you may be able to modify it to match the earlier one. OR, You may find that one of the vacuum taps will provide the appropriate style of source to achieve the desired result.
Is the desired result to supply manifold vacuum for advance at all times except idle (closed throttle)? Most throttle bodies are arranged with a port that is just above the throttle plate when the throttle is closed, and which is then exposed to manifold vacuum when the throttle is opened a small amount. The result is no vacuum advance with closed throttle, full vacuum advance with throttle opening.

Frank,
Thanks for the reply. The stop screw is broken so I am looking to replace it anyway. I am converting to the 051 distributor advance type away from the 061 cancel retard type.
Are there any other differences between the two that may cause problems?
Brad

If the bolt patterns and the throttle bores are the same, you should be good.
Just look for the vacuum port position as noted above.