360 oil pressure

I built a 360 with speed pro H116CP30 pistons, crank turned .010 (matching bearings of course), McCandless machined smog heads (2.02 1.60 cut .020 ports tapped and plugged) air gap intake, Edelbrock 750, MP high volume oil pump.

On the initial start up the oil pressure was approximately 45 psi at 2000 RPM. It's slowly decreased as it warmed up to around 25 psi. it holds 15 to 20 PSI at Idle when it's warm. But once it's nicely warmed up it only maintains 25 to 30 maximum.

It's a Mopar performance standard pressure high volume pump. Do these numbers sound right to you guys? I'm pretty sure I'm going to add the high pressure relief spring to the pump.

I have the engine in a 2700 pound street/racecar with 29 inch tall tires and a 4.56 gear. I suspect I'll finish the quarter mile around 6000 to 6500 RPM. if memory serves the general rule is 10 PSI per 1000 RPM.

Thoughts?

Laine

You failed to mention what weight oil? On the .0025-.003 builds with 30w I normally get over 75 on startup and over 30 at idle of 1000 rpm and hits 75 at any above, thats with the melling hv72 pump.

Did you do the normal breakin and drain oil and cut filter for inspection?

Im wondering what others will say.

Your idle numbers are fine, but the start up and higher rpm numbers are low. The pump is likely bleeding off pressure too soon due to a weak relief spring.
Unfortunately on a small block you need to drop the pan in order to stiffen the spring.

Are you running at least a 10w/30 oil?

Oops. Using Havoline 10-40 with zinc additive. The engine has about 20-30 minutes of break in time on it. I drove it about a 1/2 mile once and, of course had to do a little burnout for a buddy. ;-). Kept the rpm low though.

I would say it's ready to get some abuse now. But, first, I guess I'll change out the relief spring.... Yay, pulling the engine again. But, then there is that snowball effect.... I want to replace the cam. I think it needs a bit more than the 284-484 that's in it.

Laine

That's good oil pressure.. I would like more, but that's ok..

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I have the engine in a 2700 pound street/racecar with 29 inch tall tires and a 4.56 gear. I suspect I'll finish the quarter mile around 6000 to 6500 RPM. if memory serves the general rule is 10 PSI per 1000 RPM.

Thoughts?

Laine

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Its too low. I'm assuming the 3/8 pipe plug on the rear end of the dr horizontle oil gallery is in place (the one that is hidden inside), & if the oil weight is correct (I ain't an oil guy) then as said pull the pump & see what is up with it. Holler with any developments. EDIT Direct reading gauge?