Low oil pressure problem

Were having problems with my buddies 500 indy motor. Since we installed Harland rockers we seem to have lost some oil pressure. When its hot its only making 40-50 @ 6800 rpm. Ive modified the oil feed pipes to te indy heads and fitted size 60 NOS jets but dont know how much restriction I can run to these rockers. Its got a high vol oil pump fitted and I just cant figure out where were losing the pressure! Its a fairly fresh motor and we always had good pressure until we switched to the harlands. Any ideas people?

You must be getting a TON of oil up in heads and valve gear ... have you tried viewing this as the engine is running ?

Sounds like maybe there is too much clearance between the rockers..
Were these shimmed properly, and then rechecked after torqueing down the shaft..

Just my $0.00..

Your having the typical over oiling problem when using true roller rockers like Harland Sharps, T&D and so on, not bushed rockers,on a single shaft. Try restricting it down some more, are you using two restrictor jets, one in each head or one in the T block going to both heads? One is probally better than two

I didnt fit them my buddy did so not sure if they need shimming? Tbh I wasnt aware they'd need to be shimmed I thought they would be just bolt on and go! I fitted two NOS jets one in each pipe as we had to try find a solution quickly! Pressure did increase but not as much as we need! isnt the golden rule 10psi per 1000rpm? Do I need to shim these rockers or just downsize the NOS jets more?

Bump
I would like to know the best way on this subject too. Oil restriction that is.

I have a problem with restricting the oil that much
to each head when using a single shaft... it takes so
long for the oil to fill the tube and finally make
it to the push rod cup/tip which could cause a push
rod tip issue... I would rather have some pressure in
the shaft and restrict the side play and maybe even
use a simple seal on each side of the rocker to hold
more in there.... would be a whole nother game if you
were push rod oiling.... then I could see a .015
orifice in each push rod... I have .030 in each push
rod and thats more than plenty... JMO

NOT ONLY a push rod issue .... you could also TOAST valve springs.

MOST of the cooling that VSs get is from oil. But then again ....tooo much oil up-there costs HP to drive the pump THEN there is the HP loss with the crank and rods driving-through all that excess drain-back oil.

I just put on a set of HS also I was just in the garage priming the oil I have a .069 jet in each line and that is still WAY to much oil up top and I have the side clearence set at .012 so I will have to change jets

Cheers everyone I think Ill try going a little lower on the jet sizes to see if we can get the pressure back up and maybe see if I can shim them out a bit to add restriction. Can you get a shim kit for these rockers or will I just have to find some that fit? I wont get to be with the car for a couple more weeks til we get back to the track so I'll just have to wait and see how it goes I guess. I really dont wanna toast his top end so I'll just have to keep an eye on things as we go!