vacuum gauge on my 351 cleveland

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bought a vacuum gauge today for my 73 351 Cleveland and quite honestly need some guidance. car idles fine but cuts out at higher speeds. new distributer and points, carburetor rebuilt(edelbrock), spark plugs and wires are all new. Any help would be appreciated... tired of scratching my head and hair out.

 

[Don C]

I would start with fuel delivery (pump, lines & filter) and coil.

 

[[email protected]]

I would start with fuel delivery (pump, lines & filter) and coil.

new fuel pump, coil,

filter and tank. fuel pressure reads 7psi...

 

[SteveO_71]

In addition to the items Don mentioned, here is info related to the vacuum gauge.

http://www.secondchancegarage.com/public/186.cfm

What type of ignition system do you have? Is it a Pertronix? Do you have a factory tach?

If the Pertronix distributor module is wired to the + coil, that can cause an issue at higher rpms. It needs to get a full 12v.

 

[[email protected]]

In addition to the items Don mentioned, here is info related to the vacuum gauge.

http://www.secondchancegarage.com/public/186.cfm

What type of ignition system do you have? Is it a Pertronix? Do you have a factory tach?

If the Pertronix distributor module is wired to the + coil, that can cause an issue at higher rpms. It needs to get a full 12v.

stock distributor with a flame thrower coil. yes have a factory tach.

 

[Don C]

New parts are no longer a guarantee that they function properly. You will need to check fuel pressure and coil output at the engine speed where you're having the problem, preferably under load, not an easy thing to do.

 

[SteveO_71]

In addition to the items Don mentioned, here is info related to the vacuum gauge.

http://www.secondchancegarage.com/public/186.cfm

What type of ignition system do you have? Is it a Pertronix? Do you have a factory tach?

If the Pertronix distributor module is wired to the + coil, that can cause an issue at higher rpms. It needs to get a full 12v.

stock distributor with a flame thrower coil. yes have a factory tach.

Which flame thrower, the basic 1.5 ohm or II or III? By stock I'm assuming you mean points.

 

[[email protected]]

vacuum needle is staying pretty steady at 15 but seems to me should be higher...maybe 20ish?

In addition to the items Don mentioned, here is info related to the vacuum gauge.

http://www.secondchancegarage.com/public/186.cfm

What type of ignition system do you have? Is it a Pertronix? Do you have a factory tach?

If the Pertronix distributor module is wired to the + coil, that can cause an issue at higher rpms. It needs to get a full 12v.

stock distributor with a flame thrower coil. yes have a factory tach.

Which flame thrower, the basic 1.5 ohm or II or III? By stock I'm assuming you mean points.

3.0 ohms coil, yes had a pertronic igniter

but swapped back to regular point when I put new distributor in...

 

[will e]

How much vacuum you can obtain at idle depends a lot on what cam you have. Steady is good. If it is a stock 73 Cleveland than I would say you should get closer to 20 inches. If it is an older engine that will drop some.

 

[rocket366]

The definition of "cuts out" needs to be explained IMO

 

[[email protected]]

The definition of "cuts out" needs to be explained IMO

accelerating to higher speeds or putting my foot into it makes its back fire/ pop out the tail pipes.

 

[rocket366]

Copy That!

Now we need to know the condition of the engine.

On a older engine I would be looking at the compression/valve train.

Tests are in order and a visual on valve train.

reminds me of a flat cam guessing here 4 sure

Paul

 

[Don C]

Back firing indicates a lean condition. Popping in the tailpipe indicates misfiring and raw fuel burning in the tailpipe.

 

[Bill73Ragtop]

I'm thinking ignition issue at higher rpm.

 

[mjlan]

It almost sounds like a condenser, your problem sounds ignition related- it is fine at lower RPM's and load, but can't handle things at increased loads...

 

[Jeff73Mach1]

look for a bad plug or plug wire. I actually had a wire work off of a plug and while it was visually in place, the electrode was loose. Car backfired like crazy over 4000 rpm but drove fine otherwise.

I'd look for an ignition problem too. Wires get old and fail and plugs can be bad new out of the box if they were ever dropped in transit or otherwise.

 

[coilwire]

If you have an extra carb try that onec. I have had bad luck with edelbrock carbs for some reason.

Jim