Newbie here... Greg with a '70 Barracuda, 440, .40 over, M1 intake, 750 Holley, Lunati hyd flat cam.
. Has Doug's headers, 727 to a 410 Dana. Runs great to 5000 rpm then flutters. Most gurus say probably valve springs.
My choices are, to put new Edelbrock heads (84cc) on , or replace springs on the 452 stock heads. I'm getting two different opinions on the Eddys. I don't have a good grasp on quench so be gentle, lol. What's your take? Thanks.

 

With a little work you can replace the springs without removing the heads. So you are looking at less than $200 for springs or $1600 ? for heads. Make sure you cam didn't go flat

 

Springs are cheaper and less involved. But if you're looking for an excuse to bolt on some easy horsepower I think you've found it. What compression ratio does your 440 run? Those 84cc heads will bump the compression significantly, they offer 88cc as well if it's an issue.

 

Much bigger carburetor, you are choking it! And if you add the eddy heads, 950 < 1050 cfm.

 

452 aren't stock unless its a newer motor

 

I meant the 452's are later heads but stock set-up. I believe I'm at 10.5/1 compression now. Going with Edelbrock's since I got them barely used for 1/2 price. Thanks guys.

 

Check your fuel pressure first. You may be running out of fuel at WOT. I had the same problem, and after the installation of a T in the fuel line, I could see my fuel pressure going to nothing at WOT, while it was OK at low loads.

On the same engine, I also had weak springs, which got weaker and weaker and probably were responsible for wearing out the cam. But my guess is that these valve springs were 45 years old.

 

Match your springs to you cam.