I have a 383 stroker with about 5k miles on it.
I have 7-10 psi at hot idle around 850rpm with my mechanical oil pressure gauge.
It reads around 10-12 psi on the factory gauge at 850 rpm.
If i hit the brakes really hard sometimes the psi will tank down to like 5 psi for a sec or two then bounce back up.
good news is my pressure off idle:

1500rpm - 15-18 psi
2500rpm - 30psi
3500rpm -40psi
4000rpm and up towards WOT it climbs to 50-60psi with the oil being completely warmed up.
Do you see any issue with this????
motor is quite at idle, no lifter noise or knocks.
And it only has a stock oil pump, no high volume or high pressure pump !

 

are you saying it has lifter noise and knocks...or were you trying to say "no"?

you confirm oil pickup did not come off oil pump?
you running a windage tray?
was the motor built with wider bearing clearances than stock?

FWIW my 40k mi 383 has 45 psi at warm idle and 55-60 at higher RPM's

 

No knock or lifter noise at all. Runs great!!! Unsure of bearing clearances.
yeah it seems to be running around the 10 psi -1k rpm minimal except for once you get over 2500rpm.

 

10psi at idle is "ok"...just not lower than that

your OP "tanking" when you slam on the brakes...should not happen. Just confirm the oil pick up is on and you should have a windage tray.

I have a stock pan and use the stock windage tray but had to stand it off 1/8" so it would clear rods. Just used washers on the 3 longer crank studs to space it off

 

Would i have to drop the k member to drop the oil pan and check the pick up???

 

you can just use a coat hanger or something through the oil drain hole or the oil level sensor hole to feel around

You can buy one of those snorkel video cams at Harbor Freight if you wanted a "clear pic" of the inside....I see them on sale for around $65

 

The oil pump pick up falling off wouldnt have any effect on my low idle psi right? Just might explain the loss of pressure with hard braking???
im thinking of checking the oil pump drive gear too as those can strip out.
just really dont want to dig into this motor right now.
good idea with the camera!!!

 

The oil level should be high enough in pan that pump with a PU that fell off should still be able to suck up oil. Braking or turning the oil would slosh which would cause the pump to suck air

Motors where the windage tray was not put back in can foam the oil at higher RPM's causing oil pressure to drop. Sounds like your OP is fine at higher RPM's, just low at idle and hard braking which would point more to a detached oil pick-up. You would need to drop the pan to fix that

If the drive gear goes typically there is no oil pressure. If the hold down bolt gets over tightened the plastic top of drive cracks/breaks causing the drive gear to "lift away" from the cam. You will need to pull intake to look at the drive gear though.

also if the stock oil pump drive shaft was re-used the plastic color can break because it gets old/dry. Most use a ARP or Miloden solid metal oil pump drive shaft. If that color breaks you would have no oil pressurea

 

Was the oil pressure always that low since the rebuild? Or did the pressure drop over time? If it was always like that then you probably need a HV pump (like the 10552) to account for looser clearances. If it dropped over time, then you have a starvation problem. Check the pickup.

Brakes have nothing to do with oil pressure, do your rpms dip under lower than idle when you brake hard? You could need the IAC throttle follower table adjusted in the tune.

 

they do if the pump pick up is off....

Op noted oil pressure drops during hard braking...which is why it is suggested he check to see if his pick up came off

If it didn't than he needs to look further

It was asked if his motor was built with wider bearing clearances, op was "unsure"

Motors with wider bearing clearances typically run a HV pump and 20-50 oil

 

We need clarification, I'm trying to figure out if the pressure was always low since rebuild or if this was a problem that developed over time. If it's the latter, than it's likely that the motor is eating itself and he's about to need another rebuild.

Yeah, the oil pickup is a likely cause of pressure drop. Pans with deeper sumps, incorrect oil level for the pan, wrong depth pickups, and poor baffling could create the same behavior. If none of those are issues, there's no reason oil pressure should drop under hard braking though. It's not uncommon for a cammed motor to stumble slightly when coming to a stop with a crappy mail order tune which is why I brought it up.

 

Well now my clutch pedal is stuck to the floor!! What could that be??? Gotta fix this 1st before driving it again.
i bought the car already built so im not sure of what pressure it had 4k miles ago. The tune seems very good. No stumbling or misses. The car flat out rips from 1500-6500rpm.

 

typically that is because the hydraulics puked. MC more likely. Look at MC for any fluid. Or check under car for fluid leaking from slave

 

It doesn't sound good that's low psi IMO. What other changes have you made to the engine?

 

My slave cylinder blew it's seals around a year ago. Low pedal. No signs of trouble from it until I removed it. The plunger on the slave seemed to have something wrong with it....then it puked fluid everywhere when I disturbed the dust boot.....it was full of fluid.

Could be a bad throwout bearing as well.