360 heads on a small block

It is definitley a low pressure issue. It seems to be from the top end starving for oil. Both stock rocker arms are on correctly. When I first put this motor back together I had some sort of blockage which caused the oil pump shaft to break. I tore it down and put in a new pump, shaft and pickup tube. I have tried three different gauges and get the same readings. When I drive the car and accelerate I am getting about 20-25 lbs pressure but I do not want to drive the car due to the fact that I am getting such low pressure when I stop at a stop light in gear. (about 10-12 lbs max) I did install a Summit aftermarket cam which was larger than stock but I do not recall the specs on the cam. As noted before I did not change out the cam bearings due to the fact that the old cam (stock) seemed fine, I was just seeking a better "lump" to the engine idle. I got that now. It idles like a beast but the oil pressure is the issue.There seems to be some oil getting up to the top end but not enough to register sufficient readings on the gauge. With the old set up I was getting over 35 lbs psi when stopped at a light with the car in gear. Now I got to put the trans in neutral and feather the gas pedal to keep it running when I am stopped at a light. Timing is on as stated before the car starts right up and idles fine when cold but as soon as it reaches operating temperature you can hear the ticking of the lifters and especially when you drive down the road you can hear the top end noise. I thought that maybe these heads were the wrong ones and maybe needed to be milled. But I am no expert at engine work.