Carb Question

[kuch72]

I just bought a truck that was kind of thrown together by one of the previous owners. It has an Edelbrock 1407 (750 cfm) carburetor on a stock 73 350. The carb needs to be rebuilt, its not acting quite right. I am thinking that the carb is kinda big for the engine. Can it be metered down for a little better efficiency or should I just find a smaller carb, maybe with electric choke, to put on the engine?

Also, is there a good place to pick up a throttle cable for the truck?

Thanks,
Nate

[threeonthetree]

what is it doing that is acting up?

how many cfm do you think the carb is?

i'd say you could pick one up cheap at a local parts store.

[GASoline71]

You can't "meter down" a carb. You need a 600 cfm carb for your application.

You can always sell the 750 that's on there now and put it towards a new 600.

Gary

[kuch72]

The truck will only run with the choke mostly engaged

[GASoline71]

Then you have a wicked vacuum leak.

Gary

[dukcaln]

carbs way big for a stock small block but like stated you have other issues

[kuch72]

Alright so I'm new to the carb world, but trying to learn. So to get the engine to idle reliably i can just plug the vacuum ports on the carb? If i understand correctly this will just prevent my brake booster from working and vacuum advance on the distro. Is the PCV valve unrelated to vacuum?

[sean1969c10]

If you have power brakes they need to be connected to the booster, make sure that hose is in good shape. You need to have the vacuum advance connected and the PCV needs to be connected to vacuum too, you also need to make sure the crankcase has a way to pull in fresh air. The massive leak Gary is talking about could be between the carb and the manifold, the manifold and heads or any of the vacuum hoses if they are old. You can spray some carb cleaner around the base of the carb and along the manifold gaskets, if the idle picks up then that is where your leak is. Hope this helps.

[kuch72]

Alright. I got a used Holley 1850 cleaned and rebuilt it. The truck started right up I've done a little timing work, I haven't yet done the whole timing procedure, verifying TDC and all that. But my issue now is that my vacuum secondaries aren't working. I used the paperclip trick and took the truck for a drive. Now this is on a stock '73 350, Is there a chance that the engine doesn't require enough air to open the secondaries? I guess I should buy a vacuum gauge and check the vacuum.

I'm also using an adapter from square bore to spreadbore, I know this isn't the best solution. Would it help to put on an aftermarket intake manifold? (edelbrock performer)

I do plan on either rebuilding this engine or building a separate engine and swapping it in. So i could just wait to get a new engine to buy an intake manifold.

Thanks for the help,
Nate