Does anyone know how low the oil pressure can be at idle on a 327.

It is a high volume oil pump.

thanks.

General rule of thumb is 10psi for every 1000rpm. Minimum 10psi at idle with a max of about 60.
Personally, I would want a minimum of 15-20psi at idle.
Are you using a real gauge or relying on the factory in-dash gauge?

It is a aftermarket gauge, but I am getting around 20psi at idle, but it used to only go to around 30 to 40psi. Max is around 70psi. I was surprised to see it come down some more but maybey its just normal.

Thanks.

If you're using a mineral oil and it's getting quite hot, there will be a substantial drop in oil pressure at idle. Oil should not exceed 230F for good lubrication.
As for 40psi being your max, I would be concerned if it's a new and sudden change to what pressure you've normally had.
It is posible that the bypass valve's spring in your pump has insufficient tension (needs shimming or replacement, -although this is a long shot), or your oil filter has become clogged -assuming your gauge is reading pressure on the "engine side" of your filter (where it should be).
If your gauge is reading between your pump and filter, you would get a higher and bogus pressure reading from a glogged filter.

my oil pressure usually goes to around 60 to 70psi when running but at idle it has dropped and it could be that it has been doing it after it has warmed up.

I am using a straight 30 weight oil right now with a can of EOS to help break in. The oil pressure is read off of the top of the rear of the block, just at the end of the intake manifold. I don't really know where the normal place is that the oil pressure is read from.

I think it should be okay.

Thanks.

That is the factory location for the oil pressure sender. Not sure with small blocks, but big blocks are read in-between pump and filter which is misleading. (CORRECTION.. BBCs are not. They're just not at the optimum location.) Fair enough, this is not your concern right now but something to be aware of.

I would suggest a multigrade oil for more consistant pressures and I'd definitely suggest a full synthetic after you have done your run in.

Is it OK to use EOS when running in? I am not that familiar with it, but thought it was a friction modifier..

I thought that some people have been using the Engine Oil Supplement to run with the oil for the first 500 miles. Maybey it isn't a good thing, and I should be changing the oil to a multigrade. Maybey it doesn't help the engine break in when running it and it should only be use for cam break in.

Any other thoughts on this?

Maybey I will change the oil to a multigrade oil.

Thanks for the info.

"How To HotRod Big Block Chevys" mentions EOS and say is very good for a new engine. Especially the cam and lifters. (Page 119)
It's obviously not what I thought it was.

How many miles have you got on the engine so far. The rules I have always used with great success is EOS during cam break in and first 100 miles, oil change and no EOS until 500 miles, then synthetic there on out. And I always use a multiweight. As far as pressure, what do you have the idle set at? A low idle will mean low pressure. I try to make idle be 30psi or more but I had a 327 last a LONG time that idled at about 10psi.

a 1955 to 1967 small block the small journal ones run normal with 10psi idle oil pressure , they have a bit more cold with a fresh oil change but 10psi is normal , a 68 up small block for some reason will tend to have 5 to 10 psi more they will idle from 15 psi to 20 psi ? don't know why , if your motor is a small journal and has 10psi oil pressure at idle and 20 to 30 psi on the road then you are right in the groove and have nothing to worry about , as for myself I do not like the high volume oil pump's ,

You don't have a problem.

Maybe I have interpreted that statement incorrectly, but if he's saying it's come down to 40psi max, that sounds like a problem.

Is the maximum now 70psi, or 40psi?

Been gone for awhile so I haven't been able to answer.

My max is still 60 to 70psi. My idle has come down a bit, to maybey around 20psi.

I don't have hardly any miles on it yet and now will not be able to put them on until next summer.

I have about 25 miles on it.

Thanks for all the replys.