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Stroker Shivy Question

Ok I get it , this is a Mopar forum. But there are also some VERY talented engine builder here.

I have a buddy at work that has a small block Shivy stroker 410 cid I believe he said. Its 11:1 compression, good sized cam, 2" Headers and built for up to 500 shot of nitrous. Big Dominator carb running pump gas. He runs Penn 20w50 oil in it. He wont give me all his build spects soooo....


Here is what I dont understand....he said he HAS to run a vacuum pump on the engine to keep oil pressure around 50 psi. Without the vacuum pump he runs upward of 80 psi with same oil, pump and filter. He claims the pressure increase is due to the increased crankcase pressure.He had a ton of machine work done to the block, but again wont say all.


Thought of a stuck or sticking pressure relief in the oil pump?

Has no PCV system

Too thick of oil

Oil passages restricted


I just dont understand why he needs the vacuum pump? Is there something that I just dont grasp?


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That's retarded.  Why would he keep shit like that a secret? Big deal.  Anyhow, I needed a vacuum pump for my last motor I built, only because the cam was nasty and wouldn't keep enough vacuum to keep the brakes boosted up at idle.  Sounded bad ass, though... stopping was an afterthought when building lol

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I am in the process of installing a vacuum pump and on a motor with that size shot its a good idea to use one to reduce the pressure on the block. He might need one to prevent oil from puking out a breather, but mainly used to reduce stress on the motor

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