I am working on 95 LT1 383 I just finished rebuilding. It has run for about 15-20 min and there is no oil to the rockers. It was prelubed and the oil was slow getting there but slowly got some at prelubing. Now there is oil getting to the lifters but not the rockers. It has 35 PSI at 1000 and 20 cranking. Any suggestions? Could 30wt have that high a oil pressure with no plugs in the front?

They arent too tight are they, that will affect flow on 1rst gen for some reason?

sounds like you forgot to install a plug somewhere in the oil passageways. I also had this problem with a new oil pump missing the spring.

he has oil pressure but very little up top?

"Slow getting there" half the oil is bypassing & the rest is making it to the lifters. I did this on my first build up. I would get around 20psi with a HV M55 pump. found out I forgot to install the plug in the middle front behind the cam timing gear. There are also two plugs in the back in the same hole, I forget where they go though (cam related) .

I was asked about the lifters by my machinest who is trying to help me out. I did it with the intake off and by turning the push rod in my fingers until drag is felt then 3/4 turn while watching the plunger being pushed down the lifter. The book says 3/4 to 1. I usually go less but since it is for someone else I didn't want him to blow the innards out of his lifters from it riding against the clip. I am going to check the plugs (on the lifter gallerys)the best I can with a piece of wire down the oil gallery to the front. With out some plugs it will still build pressure? That is the only thing keeping me from pulling the front of the engine apart is I can't convince myself with no plugs it will build any pressure.

Well I pulled the timing chain and cover and the galley plugs are there. With the intake off I felt in the dist hole and the rear cam bearing isn't to far forward causing the oil the leak out of the groove under the bearing. Now where do I look? Would the pump be bad and still make 35 lbs?

did they do any machine work to the lifter bores?

No, the bores were left alone. The lifters are 126K stock ones that have been cleaned and reassembled with internal snap rings instead of the "paper clips". I a pretty stumped and this isn't my first engine by far. I guess it will have to come out and see if the pump is any good. Any ideas?