408w falling on its face

[jrod92]

Just finished building a 408w stroker carbed 750, fuel pressure set at 8 psi, edelbrock air gap intake, msd ignition 6al, msd distributor, .625 intake, .576 exhaust roller cam. timing set at 14 deg initial 32.5 advanced. idle is good and rpm is good until about 3000 then it just falls on its face bogs down and doesnt really pick back up. i have tried 3 different carbs and with no avail. msd box and distributor are new, tried different box and same thing happened. plugs are gapped at .050. Any ideas on what is causing this? Timing? Fuel? i am out of ideas. thanks guys

 

[mercurycapri]

I was told that you shouldn't have more than 6 psi on fuel pressure.

 

[jrichker]

Guess what? If it was still EFI, you could dump the codes and the computer would tell you what's wrong.

Turn the fuel pressure down to 4-5 PSI. Then look at the trgger sensor in the distributor as being a possible culprint. MSD means May Suddenly Die, and they are famous for causing problems.

 

[90lxcoupe]

is the pump bad? what kind of shape are the fuel lines in? A friend of myne had an issue where he was starving the motor for fuel because one of the rubber lines was actually collapsing, dunno if you have a similar problem

 

[jrod92]

Fuel lines are new -8 braided to the pump and -6 all the way to the carb I will turn down the pressure and check the distributor. Thanks

 

[KamiKaziDK]

If that doesn't work you might have to mess with your jetting or power valve on your carb, carb tuning is a fine art