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Ok, let me know when you are ready and I’ll show you how to modify it.
Is it possible to give some details of what's involved? I'm putting my solid lifter SHP back together his weekend and have long thought of restricting the oil to the heads.
 

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Discussion Starter #42
Is it possible to give some details of what's involved? I'm putting my solid lifter SHP back together his weekend and have long thought of restricting the oil to the heads.
It turns out to be very easy with the right tap Dennis. The passage is even machined out to a size Q so no drilling required. If the pics didn't explain it very good let me know and I can take a few with the tap in to illustrate.
 

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0.125 is not a restriction at all. That’s over 3mm in metric terms. It’d be pointless using them imho.
I believe the ideal orifice size in an oil restrictor has a lot to do with the viscosity of the oil. In the older days, most people used conventional 20w50, if not straight 50. Using a small 0.060" restrictor for an entire lifter bank using a heavy oil like this seems excessive. For a more modern 10w30 synthetic, I can see a 0.060" orifice being more inline. I would just be hesitant to recommend an orifice size without knowing the type of oil being used in the engine.

I use Mobil 1 15w50 synthetic. It flows a LOT better than conventional 20w50, but I would feel hesitant to use it with a really small restrictor orifice. The Price Motorsport kit came out a long time ago, and was probably desiged to be safe with the thicker oil. (0.125 to the lifter galleries and 0.090" to each cam bearing) These may not be that huge of a restriction, but I can see them saving the engine in case of a lifter or plug popping out or something else than would otherwise cause instant total oil pressure loss. Plus, even a larger restrictor is far smaller than the parent passage, and has to help some.
 

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LIFTER GALLERY RESTRICTORS:
I was able to install the lifter gallery restrictors in the Dart block. The passenger side (non-oil fiter) lifter gallery is fed by a passage in the rear, as described in the yellow instructions posted above. I was able to simply run a 1/2-13 tap through the 1/4 NPT hole in the back of the block, and tap it all the way past the oil supply, far enough into the metal beyond that to insert the restrictor. It has to be tapped DEEP... around 2.5". I did it by hand. The 1/4 NPT threads help guide the 1/2-13 tap, and keep it straight. Just be careful, go slow, keep moving it in and out... flushing out the cuttings, and it will eventually get there. The 1/4 NPT plug in the back of the block still goes in like it always did, and seals just fine.

The driver side lifter gallery (oil filter side) is a 7/16-20 plug that taps into the diagonal gallery from the top of the block. The tap didn't really want to start easily, so I read the writing on the tap, and it said to drill a 25/64 hole... so I did, and it bit. (didn't have to do that on the stock block) The tap went in about a half inch, then stopped. I didn't want to break it, but with a tiny bit of trimming to the restrictor, it was far enough to not interfere with the screw-in plug on the top of the Dart block.

This is a Dart Sportsman 8.2 block, which is basically an Iron Eagle 'Light'. The SHP wasn't out yet when I purchased it 10-ish years ago, else I probably would have gotten one of those. I'm assuming the SHP would be set up in a similar fashion.
I was studying the oiling system this evening, and there are three galleries. One for each lifter bore, and the main one. The main gallery comes from the front of the engine and feeds the main bearings on its way back, and at the rear of the block feeds the lifter galleries.

There is a passage from the main to the passenger side gallery. It goes straight up, and intersects the passenger gallery about a half inch behind the rearmost lifter. The ONLY way to restrict this gallery, is to run a 1/2-13 tap about 2.5" deep from the back of the block... past the feed hole, into the gallery... but not quite into the lifter bore. (It's detailed in the yellow PME instructions on the previous page. Use a 1/2-13 plug with your choice of orifice.

For the driver side gallery... The oil feeds from the passenger side, up the 'V' shaped passage under the plug at the top rear of the block, down to the driver side. You can tap either side of the V for a restrictor. Before, I said to use a 7/16-20 size drilled plug as a restrictor on the driver side of the 'V'. That works great in a factory block, but is the hard way in a Dart. In a Dart, the other side of the 'V' is already drilled the perfect size for a 1/4 NPT plug. Plus, it's a lot more straight up and down, so it's easier to tap. No drilling required. Just tap it for the plug, and install.

If you try to do any restricting from the front of the block, you're going to starve the mains. ONLY do it from the rear.

Good Luck
 
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