Engine bogs at 4000 rpms

[65wetherby]

I have the 289 4V with a Holley 4160 600cfm carb. The manifold is the Edelbrock performer 289. Problem is that in 3rd and 4th gear when I hit 4000 rpms the car bogs down and won't smooth out until I release the gas and the rpms drop. It runs smooth on the street until 4000 rpms. In 1st and 2nd I can jump on it and have no problems. Also, I have an electric fuel pump. Any ideas would help. Thanks.

 

[nds03]

sounds like your carb is running lean. get some bigger jets in it, check float level.

 

[ron67fb]

In 1st and 2nd I can jump on it and have no problems.

Does that mean you can go over 4000rpm no problems in 1st and 2nd, and only get the bog in 3rd and 4th over 4000rpm?

What else can you tell us about your engine? With 40 year old valve springs, a stock cam, heads, and exhaust you'll be lucky to get over 4000rpm at all.

 

[65wetherby]

1st and 2nd I can go over 4000 rpms but not in 3rd and 4th. Purchased the car last summer and tore the engine down to the head gaskets. Put a new cam in, timing chain, new push rods, etc. I'm checking the float levels this morning.

 

[Max Power]

Replace the fuel filter while you are at it. Since it will rev willingly above that in 1st or 2nd, ignition can pretty much be ruled out.

Quite often a car will rev fine in the lower gears because it revs pretty fast down there, but fail in higher gears because it revs slower and takes more fuel to get the job done.

It really sounds like low fuel in the float bowl, probably caused by a fuel filter that is partially clogged.

 

[65wetherby]

I pulled the float bowls off the carb and found that the secondary float was stuck to the bottom and has not been receiving any fuel!! That was a quick adjustment. Thanks everyone for all of the help. Now if I can get the fuel to stop getting around my fuel rod life will be good.

 

[ron67fb]

Uh, stuck to the bottom, or to the top? If it was stuck to the bottom the carb would be flooding unless the needle happened to be stuck up at the same time.

edit - Oh wait, I get it. The needles were screwed all the way down? Nice one.

Now if I can get the fuel to stop getting around my fuel rod life will be good.

???