For my new stroker, I installed a Melling 10687 pump from their Select line of pumps. When I fired the installed engine, I had 45-50 cold psi of oil pressure, which I wasn’t satisfied with.
Melling Select line oil pumps come with an alternate bypass spring and an Allen head screw-in plug in place of the usual cup plug. My hardcore Ford friend Andy and I dropped the oil pan Saturday to swap in the alternate “green” spring that Melling says will raise oil pressure. This saves you the trouble of removing a soft plug and shimming the spring with hardware store washers, as we did on the standard M68 pumps back during the 5.0 Mustang craze.
Side tip: On a '68, you can drop the oil pan by removing the tubular unit body brace and the idler arm to lower the steering. This was easy using Andy’s lift.
Upon reassembly and firing, we had 90 psi cold oil pressure (Valvoline ZR-1 20W-50) versus 45-50 (diesel 15W-40) with the default spring. For reference, my main bearing clearances are .002-.0025, and rods a bit tighter (I assembled it).
I wanted to post these real-world data so someone can search “oil pumps” in the future when building or rebuilding a short block and find them.
Thanks for this information. I recently visited with Jay Brown (FE Power LLC) and believe he was making a similar modification on his dyno mule. He was noticing a slight drop in oil pressure but higher up in the RPM range if my memory is correct.
I use this oil pump in my '67 race car. It has a unique feature where the rotor is supported through a hole in the bottom of the pump cover.
This may cost some HP but it should help stabilize the oil pump drive shaft at high rpm.
Thanks for posting, this is very timely for me, as I need to drop my oil pan on my 68. I put a new style one piece gasket in, and it *******leaks. I wouldn’t have thought about having to drop the steering down, and I wasn’t sure if removing the cross member alone would get it. Do you think I could get away without dropping the steering, just to do the gasket?