Timed or Full Vacuum???

[skink4president]

On my '73 K5 I've used both. Don't have the original Q-jet so I'm not sure if it came stock with both or which was used. Edelbrock calls for "timed" vacuum on emmisions vehicles and full or "manifold" vacuum on non-emissions. The '73 came with emissions (not CA) but all has since been lost. Would I see a performance or mileage difference with one or the other? Right now I'm using timed and running an HEI and Edelbrock Performer square bore.

Thanks!

PS-I did a search of the forum using the above title but nothing came up. If we get some replies to this one maybe it'll provide a hit for others looking for an answer to this question.

 

[pauly383]

You'll save gas at part throttle cruise in high gear if you use Ported vacuum .

 

[skink4president]

Ported is "timed", right?

 

[pauly383]

Yes , but I don't like saying timed .

 

[Triaged]

It shouldn't make for any performance or mileage difference. The only thing it will effect it idle. Mine idles better with it on full vacuum. Try both and use what works best.