I have been trying to get this figured out for a week now, I hope someone here has some new ideas.
I have a fresh 540 its pulls 477hp and 540tq @ the rear wheels. the way the motor acts it defintly could run better. On cold start up I have 6.5 lb of fuel pressure and a good idle @ 800 rpm as the motor heats up fuel pressure drops.
It get fuel just low plessure.I replaced the holley red with a new holley blue pump and new regulator, same problem (I am using 1/2 fuel line). With the idle problem it will idle nice then want to die, I will turn up the idle 5 minutes later its racing then I need to turn it back down. there is also a vacuum issue @ idle it pulls about 7" then when you hit the gas the vacuum shoots up to about 20". there is no sign of an internal or external vacuum leaks. Please help if you can. :confused: :confused: :confused:

Thanks
Ron

Are you using a return line to the tank? Without one the pressure will fluctuate a little.

What is your initial timing set to? Are you running vacuum advance? When does your mechanical advance come in?

the tank does not have a return line. i tried using a gas can and bypass the tank with the same promlem. the base timing is 13' and about 32' total advance. I can't seam to get any more since recurving the distributor to about 2800. did have 38' when dynoed (hard start when hot). vac. advance not hooked up yet, I will hook it up and see if it helps.

Yup, you do not have enough initial timing for your cam, and not enough vacuum for the vacuum canister to work properly. Should be at least 18deg while you are idleing. Probably when you increase the idle speed the mechanical starts to come in and that's why the rpms continue to creep up. MSD has a starter saver module that retards the timing during startup.

When you run a dead headed pump, the pressure will drop a couple of psi from your setting at idle. Not too much you can do about it except to be certain that it doesn't drop any further as rpms go up.

TJC
Thanks, I will give that a try