Do I need to hook up vacuum?

[Hogger54]

So I'm thinking about a test fire soon, but need to sort out a few more things.
One is the vacuum. It's a 235 with an HEI dist. and dual Rochester's on a Fenton intake. Not going to run the vacuum wipers.
What do I do with the vacuum port on the distributor? Can I cap it? Does it need to run to the carbs? Or just into the intake somewhere? I read something about a vacuum bolt on the block too. Where is that, and does that come into play?

[OrrieG]

Both my HEIs (stock GM units) have have vacuum from the carb port to advance the mechanicsm. The engine will start and idle but since the dist is not advancing the timing driving will be a chore. It needs to come from the carb fitting for the dist, it is designed to read the correct vaccum for the dist. Other fittings on the carb, base and manifold are just use to capture vacuum for the wipers, auto trans and brake booster. If you are running an auto, vacuum is need to determine shift points, brakes will work without a booster but I would not risk wrecking my truck. Don't know of any vacuum ports on the block, can't image where they would pull from.

[Hogger54]

Ok, so after more research. I need to hook the vacuum line to this port next to the idle screw, but I only need to hook it up to one carb. This sound/look right?

Thanks.

[OrrieG]

Yes that is the distributor vaccum port. Originally there should have been a hard line from that to the dist. You only need to hook up the primary carb, make sure the other(s) have the port blocked off.

[Hogger54]

Awesome. Thanks.