the tank is a replacement tank should not have any crud in it. the tanks is i am going to say about 2 years old since i got it. a lot of things are pointing to my fuel pump. When i am driving the car not getting on it its fine. as soon as the pedal is to the metal at stand still first second is good right at the end of second right when i am going to get into 3rd is when i just get dropped on my face and loose power then it shuts off. I have an MSD HEI setup on my chevelle which is also about 2 years old. Again when i start the car it after sitting say a week or so it struggles to start i have to crank it a few times then it will start up. and i always see the fuel pressure sitting about 3 psi which to me i thought was too weak. I was told by some of the guys here that is fine.
http://chevelleforum.org/showthread.php?t=4280
i know that when i revved it up it was not under load it was just revved up. So i am thinking that when its under load and i rev it up it must be very low and just runs out of fuel. I dont think its spark because of the original post where i filled the bowls with gas and it started right up.
not to make this a long story but my neighbor has a 70 chevelle and his chevelle suffers from the struggle start up as well when he lets it sit for a while. he finally put a fuel pressure gauge on his and he is also seeing 3psi which makes us both wonder if we have bad fuel pumps. I have not started my chevelle since saturday 9/21 if i go home today i am going to have to crank it for about 15 seconds stop look at my gauge which it will be still at 0 crank it again then i will see it move up then it will start. hope this info helps some...lol